小惠珠哦

这个屌丝很懒，什么也没留下！

热门标签

C++大作业——学生选课系统_c++学生选课系统

作者：小惠珠哦 | 2024-07-06 01:59:12

踩

c++学生选课系统

C++大作业——学生选课系统

前言
1.系统概述
2.系统设计
3.完整代码
4.总结与展望
- 4.1设计总结
- 4.2设计展望

前言

本次课程设计是我第一次独自完成这样一个相对完整的项目，收获很多。但是我更想说一下本次设计中存在的不足。

首先就是在最初设计课程类和学生类时，没有考虑的那么全面，导致出现了很多冗余的接口，和公有私有混着用的情况。其次就是，虽然是用C++写的，却没有把封装体现出来，使用了很多friend友元函数也破坏了类的封装效果。

由于我最开始是在Linux系统上编写的代码，没有装中文包，所以很多注释和输出语句都是用英文写的。后来又转到Windows下的VS环境下编程，也写了一些中文的语句。导致会有中英文混用的情况，可能会影响观感。

在学习这个系统之前，建议先把学生成绩管理系统熟练掌握，掌握最基本的增删改查操作，我在本文中就不再赘述了，把重点放在选课和退选的功能讲解上。

在最后面，我也会把整个项目代码都放出来，大家可以拿去在自己的电脑上运行，应付下作业铁定是没问题的（手动狗头）。

1.系统概述

本系统是学生选课系统，主要是实现大学生的选课需求。进入系统，需要先选择用户（学生或管理员），选择管理员，需要输入对应的密码。选择完身份后，进入主菜单，会出现两个子菜单，学生菜单和课程菜单，选择相应的选项，就会进入相应的菜单，其中0选项是返回上级目录。

进入课程菜单，会看到增删改查相应的操作，还有显示全部课程信息。其中，学生用户没有对课程进行增删改的权利。管理员是超级用户，有所有操作的权利。里面的细节我们在模块的具体实现时再说。

进入学生菜单，也会看到增删改查相关的操作，还有显示全部学生的信息。不同的是，学生菜单中可以进行选课和退选的相关操作。学生用户只有查看信息，选课退选的权利，没有增删改的权利。具体细节也是放在模块中详谈。

2.系统设计

2.1概要设计

在这里插入图片描述

2.2详细设计

2.2.1学生类和课程类模块设计

int flag = 0;                   // default is student

class Course 
{
public:
    friend void Input_course(vector<Course>& cour);
    friend void Delete_course(vector<Course>& cour);
    friend void Modify_course(vector<Course>& cour);
    friend void Lookup_course(vector<Course>& cour);
    friend void Show_course(vector<Course>& cour);
    friend void Add_course(vector<Course>& cour);                                                                       
    friend int Read_course(vector<Course>& cour);
    friend void Write_course(vector<Course>& cour, int n);

    const char* c_id() { return id; }
    const char* c_name() { return name; }
    const bool c_nature() { return nature; }

    Course()
        : id("None")
        , name("None")
        , count(0)
    {}

public:
    char id[20];
    char name[20];
private:
    bool nature;            // 0 indicates elective and 1 indicates compulsory
    int hour;               // class time                                                                             
    int credir;             // credit
public:
    int count;              // count of student 0-60
};

class Student
{
public:
    friend void Input_stu(vector<Student>& stu);
    friend void Delete_stu(vector<Student>& stu);
    friend void Modify_stu(vector<Student>& stu);
    friend void Lookup_stu(vector<Student>& stu);
    friend void Add_stu(vector<Student>& stu);
    friend void Show_stu(vector<Student>& stu);
    friend int Read_stu(vector<Student>& stu);
    friend void Write_stu(vector<Student>& stu, int n);

    friend void Select(vector<Course>& cour, vector<Student>& stu);
    friend void Deselect(vector<Course>& cour, vector<Student>& stu);
public:
    char _id[20];
    char _class[20];
    char _name[20];
    Course _cour_compulsory[2];
    Course _cour_elective[1];
    int _num_compulsory = 0;
    int _num_elective = 0;
};

vector<Course> cour;
vector<Student> stu;
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61

在这个模块中，我设计了两个类来分别存储学生和课程的信息。课程的相关信息包括，课程编号、课程名、课程类型（选修/必修）、学时、学分、以及选课人数。其中规定，每门课选课人数最多不超过60人。还设计了一个构造函数，将课程的编号和课程名都定义为None。

学生类中，相关信息包括，学号、班级、姓名、所选择的必修课信息、所选的选修课信息、所选必修课数量、所选选修课数量。其中规定，每名学生所选必修课不超过两门，选修课不超过一门。

在接下来的增删查改操作中，我使用了全局变量cour，和stu这两个动态数组来分别存储课程和学生。其中全局变量flag是一个确定身份状态的变量，默认是0，学生用户。1是超级用户。

2.2.2文件信息读取和录入模块设计

void Write_course(vector<Course>& cour, int n)
{
    fstream myfile;
    myfile.open("course.txt", ios::out | ios::binary);
    if (!myfile)
    {
        cout << "ERROR!course.txt can't open." << endl;
        abort();
    }

    myfile << n << endl << endl;
    for (int i = 0; i < n; i++)
    {
        myfile << cour[i].id << "\t" << cour[i].name << "\t"
            << cour[i].nature << "\t" << cour[i].hour << "\t"
            << cour[i].credir << "\t" << cour[i].count << endl;
    }
    myfile.close();
}

int Read_course(vector<Course>& cour)
{
    cour.clear();                           // clear
    fstream myfile;
    myfile.open("course.txt", ios::in | ios::binary);
    if (!myfile)
    {
        cout << "ERROR!course.txt can't open." << endl;
        abort();
    }

    int n;                                  // count of course
    myfile.seekg(0);
    myfile >> n;

    Course temp;
    for (int i = 0; i < n; i++)
    {
        myfile >> temp.id >> temp.name >> temp.nature
            >> temp.hour >> temp.credir >> temp.count;
        cour.push_back(temp);           // push_back
    }

    myfile.close();
    return n;
}

// 学生数据的文件操作
void Write_stu(vector<Student>& stu, int n)
{
    fstream myfile;
    myfile.open("student.txt", ios::out | ios::binary);
    if (!myfile)
    {
        cout << "ERROR! student.txt can't open!" << endl;
        abort();
    }

    myfile << n << endl << endl;
    for (int i = 0; i < n; i++)
    {
        myfile << stu[i]._id << "\t" << stu[i]._class << "\t"
            << stu[i]._name << "\t" 
            << stu[i]._cour_compulsory[0].c_id()   << "\t"
            << stu[i]._cour_compulsory[0].c_name() << "\t"
            << stu[i]._cour_compulsory[1].c_id()   << "\t"
            << stu[i]._cour_compulsory[1].c_name() << "\t"
            << stu[i]._cour_elective[0].c_id()     << "\t"
            << stu[i]._cour_elective[0].c_name()   << "\t"
            << stu[i]._num_compulsory << "\t" << stu[i]._num_elective << endl;
    }

    myfile.close();
}

int Read_stu(vector<Student>& stu)
{
    stu.clear();                            // clear
    fstream myfile;
    myfile.open("student.txt", ios::in | ios::binary);
    if (!myfile)
    {
        cout << "ERROR! student.txt can't open!" << endl;
        abort();
    }

    int n;
    myfile.seekg(0);
    myfile >> n;

    Student temp;

    for (int i = 0; i < n; i++)
    {
        myfile >> temp._id >> temp._class
            >> temp._name
            >> temp._cour_compulsory[0].id
            >> temp._cour_compulsory[0].name
            >> temp._cour_compulsory[1].id
            >> temp._cour_compulsory[1].name
            >> temp._cour_elective[0].id
            >> temp._cour_elective[0].name
            >> temp._num_compulsory >> temp._num_elective;
        stu.push_back(temp);            // push_back
    }

    myfile.close();
    return n;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109

这里，我利用了两个文件，一个course.txt来存放课程信息，一个student.txt来存放学生信息。写入文件的第一个数据一定是课程，学生的数量。在调用Write函数要传一个数量进入。

需要注意，在向文件中写入学生的信息时，我并没有将学生成员变量中，_cour_compulsory和_cour_elective数组中的信息全部写入，只是写入的学生所选课程的编号和课程名。

2.2.3增删改查模块设计

void Input_course(vector<Course>& cour)
{
    system("cls");
    cour.clear();
    int i = 0;
    char sign = '0';
    Course temp;

    cout << "=============== Please input the massage ===============" << endl;
    while (sign != 'n' && sign != 'N')
    {
    loop:
        cout << "ID: ";
        cin >> temp.id;

        int c = 0;
        while (c < i)
        {
            c++;
            if (!strcmp(temp.id, cour[i - c].id))
            {
                cout << "ID repeat, please input again." << endl;
                goto loop;
            }
        }

        cout << "name of course: ";
        cin >> temp.name;
        cout << "elective or compilsory(0 or 1): ";
        cin >> temp.nature;
        cout << "class hour: ";
        cin >> temp.hour;
        cout << "credir: ";
        cin >> temp.credir;
        temp.count = 0;                 // the default is 0

        cour.push_back(temp);           // push_back

        cout << "whether continue(y or n): ";
        cin >> sign;
        i++;
    }

    Write_course(cour, i);                  // save
}

void Delete_course(vector<Course>& cour)
{
    system("cls");
    int n = Read_course(cour);
    int i = 0;
    char id[20];
    cout << "=============== Delete the message of course ===============" << endl;
    cout << "please input the ID of course which you want to delete: ";
    cin >> id;
    while (i < n && strcmp(id, cour[i].id))
        i++;

    if (i == n)
    {
        cout << "no fount." << endl;
        system("pause");
        return;
    }
    else
    {
        if (cour[i].count)
        {
            cout << "所选人数不为零，请联系所有学生退课后，再修改课程信息。" << endl;
            system("pause");
            return;
        }
    }

    for (int j = i; j < n - 1; j++)
        swap(cour[j], cour[j + 1]);

    // save
    char sign;
    cout << "whether delete(y or n): ";
    cin >> sign;
    if (sign != 'n' && sign != 'N')
    {
        cour.erase(cour.end() - 1);
        Write_course(cour, n - 1);
        cout << "=============== Delete succeed ===============" << endl;
    }
}

void Modify_course(vector<Course>& cour)
{
    system("cls");
    int n = Read_course(cour);                      // count of course
    char id[20];
    int i = 0;

    cout << "=============== Modify course ===============" << endl;
    cout << "input the ID of course you want to modify: ";
    cin >> id;
    while ( i < n && strcmp(id, cour[i].id))        // i < n 要提前判断
        i++;

    if (i == n)
    {
        cout << "no found." << endl;
        system("pause");
        return;
    }
    else
    {
        if (cour[i].count)
        {
            cout << "所选人数不为零，请联系所有学生退课后，再修改课程信息。" << endl;
            system("pause");
            return;
        }
    }

    cout << "----------------------------------------------------" << endl;
    cout << "ID" << "\t" << "name" << "\t" << "nature" << "\t"
        << "hour" << "\t" << "credir" << "\t" << "count" << endl;
    cout << "----------------------------------------------------" << endl;
    cout << cour[i].id << "\t" << cour[i].name << "\t" << cour[i].nature << "\t"
        << cour[i].hour << "\t" << cour[i].credir << "\t" << cour[i].count << endl;

    cout << "please reenter the message of course." << endl;
    cout << "name of course: ";
    cin >> cour[i].name;
    cout << "elective or compilsory(0 or 1): ";
    cin >> cour[i].nature;
    cout << "class hour: ";
    cin >> cour[i].hour;
    cout << "credir: ";
    cin >> cour[i].credir;

    // save
    char sign;
    cout << "whether save the data(y or n): ";
    cin >> sign;
    if (sign != 'n' && sign != 'N')
    {
        Write_course(cour, n);
        cout << "=============== Modify succeed ===============" << endl;
        system("pause");
    }
}

void Lookup_course(vector<Course>& cour)
{
    system("cls");
    int n = Read_course(cour);
    int i = 0;
    char id[20];

    cout << "=============== Lookup the course ===============" << endl;
    cout << "please input the course ID you want to seek: ";
    cin >> id;

    while (i < n && strcmp(id, cour[i].id))
        i++;

    if (i == n)
    {
        cout << "no found." << endl;
    }
    else
    {
        cout << "---------------------------------------------" << endl;
        cout << "ID: " << cour[i].id << endl;
        cout << "name: " << cour[i].name << endl;
        cout << "nature: " << (cour[i].nature ? "compulsory" : "elective") << endl;
        cout << "class hour: " << cour[i].hour << endl;
        cout << "credir: " << cour[i].credir << endl;
        cout << "student count: " << cour[i].count << endl;
    }
    system("pause");
}

void Show_course(vector<Course>& cour)
{
    system("cls");
    int n = Read_course(cour);

    cout << "================ display all course ================" << endl;
    cout << "----------------------------------------------------" << endl;
    cout << "ID" << "\t" << "name" << "\t" << "nature" << "\t"
        << "hour" << "\t" << "credir" << "\t" << "count" << endl;

    cout << "----------------------------------------------------" << endl;
    for (int i = 0; i < n; i++)
    {
        cout << cour[i].id << "\t" << cour[i].name << "\t" << cour[i].nature << "\t" << cour[i].hour << "\t" << cour[i].credir << "\t" << cour[i].count << endl;
    }
    system("pause");
}

void Add_course(vector<Course>& cour)
{
    system("cls");
    int n = Read_course(cour);
    char sign = '0';
    Course temp;

    cout << "=============== add course ===============" << endl;
    while (sign != 'n' && sign != 'N')
    {
    loop:
        cout << "ID: ";
        cin >> temp.id;
        int c = 0;
        while (c < n)
        {
            c++;
            if (!strcmp(temp.id, cour[n - c].id))
            {
                cout << "ID repeat, please input again." << endl;
                goto loop;
            }
        }

        cout << "name of course: ";
        cin >> temp.name;
        cout << "elective or compulsory(0 or 1): ";
        cin >> temp.nature;
        cout << "class hour: ";
        cin >> temp.hour;
        cout << "credir: ";
        cin >> temp.credir;
        temp.count = 0;

        n++;

        cour.push_back(temp);

        cout << "whether continue(y or n): ";
        cin >> sign;
    }

    // save
    Write_course(cour, n);
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241

Input函数只适用于第一次数据的录入，如果文件中有数据，使用Input函数会将原内容覆盖。追加课程使用函数Add。

关于课程的增删改查，没有太多要说的点，需要注意一个细节，就是如果该课程的选课人数不为零，那么是不允许对该课程进行修改或删除操作的，需要先联系选该课的学生全部退选，才可以进行修改或删除，不然就太坑了。

删除课程时，我使用了算法库中的函数swap，这个函数的参数是一个模版参数，可以交换任意类型的数据。

void Input_stu(vector<Student>& stu)
{
    system("cls");
    stu.clear();
    int i = 0;
    char sign = '\0';
    Student temp;

    cout << "============ please input the message ============" << endl;
    while (sign != 'n' && sign != 'N')
    {
    loop:
        cout << "student ID: ";
        cin >> temp._id;

        int c = 0;
        while (c < i)
        {
            c++;
            if (!strcmp(temp._id, stu[i - c]._id))
            {
                cout << "ID repeat, please input again." << endl;
                goto loop;
            }
        }

        cout << "name: ";
        cin >> temp._name;
        cout << "class: ";
        cin >> temp._class;

        stu.push_back(temp);            // push_back
        cout << "whether continue(y or n): ";
        cin >> sign;
        i++;
    }
    Write_stu(stu, i);
}

void Delete_stu(vector<Student>& stu)
{
    system("cls");
    int n = Read_stu(stu);
    int m = Read_course(cour);  // number of course
    int i = 0;
    char id[20];

    cout << "============ delete student ============" << endl;
    cout << "please input the ID of student who you want to delete: ";
    cin >> id;

    while (i < n && strcmp(id, stu[i]._id))
        i++;

    if (i == n)
    {
        cout << "no fount." << endl;
        system("pause");
        return;
    }

    if (stu[i]._num_compulsory)
    {
        while (stu[i]._num_compulsory > 0)
        {
            stu[i]._num_compulsory--;

            int c = 0;
            while (c < m)
            {
                if (!strcmp(stu[i]._cour_compulsory[stu[i]._num_compulsory].id, cour[c].id))
                {
                    cour[c].count--;
                    break;
                }
                c++;
            }
        }
    }
    else if (stu[i]._num_elective)
    {
        while (stu[i]._num_elective > 0)
        {
            stu[i]._num_elective--;

            int c = 0;
            while (c < m)
            {
                if (!strcmp(stu[i]._cour_elective[stu[i]._num_elective].id, cour[c].id))
                {
                    cour[c].count--;
                    break;
                }
                c++;
            }
        }
    }

    for (int j = i; j < n - 1; j++)
        swap(stu[j], stu[j + 1]);

    // save
    char sign;
    cout << "whether delete(y or n): ";
    cin >> sign;
    if (sign != 'n' && sign != 'N')
    {
        stu.erase(stu.end() - 1);
        Write_stu(stu, n - 1);
        Write_course(cour, m);
        cout << "============ delete succeed ============" << endl;
        system("pause");
    }
}

void Modify_stu(vector<Student>& stu)
{
    system("cls");
    int n = Read_stu(stu);
    char id[20];
    int i = 0;

    cout << "============ Modify the message of student ============" << endl;
    cout << "please input the ID of student who you want to modify: ";
    cin >> id;

    while (i < n && strcmp(id, stu[i]._id))
        i++;

    if (i == n)
    {
        cout << "no found." << endl;
        system("pause");
        return;
    }

    cout << "-------------------------------------------------------" << endl;
    cout << "ID: " << stu[i]._id << endl;
    cout << "class: " << stu[i]._class << endl;
    cout << "name: " << stu[i]._name << endl;
    cout << "-------------------------------------------------------" << endl;

    cout << "please reenter the message." << endl;
    cout << "class: ";
    cin >> stu[i]._class;
    cout << "name: ";
    cin >> stu[i]._name;

    // save
    char sign;
    cout << "whether save the data(y or n): ";
    cin >> sign;
    if (sign != 'n' && sign != 'N')
    {
        cout << "modify succeed." << endl;                                                                                    
        Write_stu(stu, n);
        system("pause");
    }
}

void Lookup_stu(vector<Student>& stu)
{
    system("cls");    
    int n = Read_stu(stu);
    Read_course(cour);
    int i = 0;
    char id[20];  
    
    cout << "============ Lookup the score of student ============" << endl;    
    cout << "please input the ID of student you want to seek: ";
    cin >> id;

    while (i < n && strcmp(id, stu[i]._id))
        i++;
    
    if (i == n)
    {
        cout << "no found." << endl;
    }
    else
    { 
        cout << "ID: " << stu[i]._id << endl;
        cout << "class: " << stu[i]._class << endl;
        cout << "name: " << stu[i]._name << endl;
        cout << "compulsory: " << (!strcmp(stu[i]._cour_compulsory[0].id, "None") ? "None" : stu[i]._cour_compulsory[0].c_name())
             << " " 
             << (!strcmp(stu[i]._cour_compulsory[1].id, "None") ? "None" : stu[i]._cour_compulsory[1].c_name()) 
             << endl;
        cout << "elective: " 
             << (!strcmp(stu[i]._cour_elective[0].id, "None") ? "None" : stu[i]._cour_elective[0].c_name()) 
             << endl;
    }
    system("pause");
}

void Add_stu(vector<Student>& stu) 
{
    system("cls");
    int n = Read_stu(stu);
    char sign = '0';
    Student temp;

    cout << "============ add student ============" << endl;
    while (sign != 'n' && sign != 'N')
    {
    loop:
        cout << "student ID: ";
        cin >> temp._id;

        int c = 0;
        while (c < n)
        {
            c++;
            if (!strcmp(temp._id, stu[n - c]._id))
            {
                cout << "ID repeat, please input again." << endl;
                goto loop;
            }
        }

        cout << "class: ";
        cin >> temp._class;
        cout << "name: ";
        cin >> temp._name;
        n++;

        stu.push_back(temp);                    // push_back

        cout << "whether continue(y or n): ";
        cin >> sign;
    }

    // save
    Write_stu(stu, n);
}

void Show_stu(vector<Student>& stu)
{   
    system("cls");                                                                                                        
    int n = Read_stu(stu);

    cout << "============================ diplay all student ==========================" << endl;
    cout << "ID" << "\t" << "class" << "\t" << "name" << "\t" 
         << "compulsory" << "\t\t" << "elective" << endl;   
    cout << "--------------------------------------------------------------------------" << endl;
    for (int i = 0; i < n; i++)
    {
        cout << stu[i]._id << "\t" << stu[i]._class << "\t" << stu[i]._name << "\t" 
            << (!strcmp(stu[i]._cour_compulsory[0].id, "None") ? "None" : stu[i]._cour_compulsory[0].name)
            << " "
            << (!strcmp(stu[i]._cour_compulsory[1].id, "None") ? "None" : stu[i]._cour_compulsory[1].c_name())
            << "\t"
            << (!strcmp(stu[i]._cour_elective[0].id, "None") ? "None" : stu[i]._cour_elective[0].c_name()) 
            << endl;
    }

    system("pause");
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258

以上是学生信息的增删查改，细节较多，在这里一一说明。首先，删除学生时，如果该学生选的有课，那么将学生删除后，对应课程的选课人数也应该减减；其次，打印学生所选课程时，需要先判断课程的id是否为None，如果是就打印None，表示没有选课，id不为None就说明选的有课，就打印该课程的课程名。

2.2.4登入模块设计

int choose_user()
{
loop:
    system("cls");
    int c = 0;
    cout << "=================================================================" << endl;
    cout << "-------------- welcome to course selection system ---------------" << endl;
    cout << "please choose your identity, admin or student(1 or 2)(input 0 to exit): ";
    cin >> c;

    char passwd[20];
    if (c == 1)
    {
        cout << "please input password: ";
        cin >> passwd;
        if (!strcmp(passwd, "123456"))
        {
            flag = 1;
            cout << "log on succeed." << endl;
            system("pause");
        }
        else
        {
            cout << "password error." << endl;
            system("pause");
            goto loop;
        }
    }
    else
        flag = 0;

    if (c < 0 || c > 2)
    {
        cout << "please input 0-2." << endl;
        system("pause");
        goto loop;
    }

    return c;
}

void menu_course()
{
    int c = 0;
    while (1)
    {
        system("cls");
        cout << "============ menu of course ============" << endl;
        cout << "               1. input                 " << endl;
        cout << "               2. delete                " << endl;
        cout << "               3. modify                " << endl;
        cout << "               4. lookup                " << endl;
        cout << "               5. add                   " << endl;
        cout << "               6. show all              " << endl;
        cout << "               0. return                " << endl;
        cout << "----------------------------------------" << endl;
        cout << "please choose your operation(0-6): ";
        cin >> c;
        switch (c)
        {
        case 1:
            if (flag)
                Input_course(cour);
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;
        case 2:
            if (flag)
                Delete_course(cour);
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;
        case 3:
            if (flag)
                Modify_course(cour);
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;
        case 4:
            Lookup_course(cour);
            break;
        case 5:
            if (flag)
                Add_course(cour);
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;
        case 6:
            Show_course(cour);
            break;
        case 0:
            cout << "------------ return succeed ------------" << endl;
            system("pause");
            return;
        default:
            cout << "please input 0-6." << endl;
            system("pause");
            break;
        }
    }
}

void menu_student()
{
    int c = 0;
    while (1)
    {
        system("cls");
        cout << "============ menu of student ============" << endl;
        cout << "               1. input                 " << endl;                                                        
        cout << "               2. delete                " << endl;                                                         
        cout << "               3. modify                " << endl;                                                          
        cout << "               4. lookup                " << endl;                                                           
        cout << "               5. add                   " << endl;
        cout << "               6. show all              " << endl;
        cout << "               7. select course         " << endl;
        cout << "               8. deselect              " << endl;
        cout << "               0. return                " << endl;
        cout << "----------------------------------------" << endl;                                                          
        cout << "please choose your operation(0-6): ";
        cin >> c;
        switch (c) 
        {
        case 1:                                                                                                                        
            if (flag)
                Input_stu(stu);
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;                                                                                                         
        case 2:
            if (flag)                                                                                                                   
                Delete_stu(stu);                                                                                                 
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;                                                                                                         
        case 3:                                                                                                                       
            if (flag)                                                                                                             
                Modify_stu(stu);                                                                                           
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;                                                                                                       
        case 4:                                                                                                                     
            Lookup_stu(stu);                                                                                                   
            break;                                                                                                       
        case 5:                                                                                                                    
            if (flag)                                                                                                                      
                Add_stu(stu);                                                                                              
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;                                                                                                      
        case 6:                                                                                                                   
            Show_stu(stu);                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
            break;
        case 7:
            Select(cour, stu);
            break;
        case 8:
            Deselect(cour, stu);
            break;
        case 0:
            cout << "------------ return succeed ------------" << endl;
            system("pause");
            return;
        default:
            cout << "please input 0-6." << endl;
            system("pause");
            break;
        }
    }
}

int menu_main()
{
    int c = 0;
    while (1)
    {
        system("cls");
        cout << "====================================================" << endl;
        cout << "               1. course message                    " << endl;
        cout << "               2. student message                   " << endl;
        cout << "               0. go back to higher-leve menu       " << endl;
        cout << "choose your operation: ";
        cin >> c;

        if (c < 0 || c > 2)
        {
            cout << "please input 0-2." << endl;
            system("pause");
        }
        else
            break;
    }

    return c;
}


int main()
{
    cour.reserve(100);
    stu.reserve(100);
    while (1)
    {
    loop:
        if (!choose_user())
        {
            cout << "=============== thank you for using ===============" << endl;
            return 0;
        }
        while (1)
        {
            switch (menu_main())
            {
            case 1:
                menu_course();
                break;
            case 2:
                menu_student();
                break;
            case 0:
                cout << "=============== return scceed ===============" << endl;
                system("pause");
                goto loop;
            default:
                cout << "please input 0-2." << endl;
                system("pause");
                break;
            }
        }
    }
    return 0;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256

可以看到，在进入系统后，需要先选择用户，如果选择管理员身份登入需要输入密码，选择学生身份则不用。随后会进入主菜单，有三个选项，1.课程菜单，2.学生菜单，0.返回上级目录。选择1或2就会跳转到相应的子菜单，选择0则会回到选择用户身份的界面。进入子菜单后，可以看到，课程菜单和学生菜单的前几个选项是一样的，唯一不同的是学生菜单中多了两个选项，选课和退选。

选择身份界面：

在这里插入图片描述

主菜单：

在这里插入图片描述

子菜单：

在这里插入图片描述

2.2.5选课模块设计

void Select(vector<Course>& cour, vector<Student>& stu) 
{
    system("cls");
    int n_cour = Read_course(cour);
    int n_stu = Read_stu(stu);   
    int i = 0;              // student
    int j = 0;              // course

    char id_c[20];          // course  
    char id_s[20];          // student                                                                               
    cout << "============ select system ============" << endl;
    cout << "please input the ID of student: ";
    cin >> id_s;
    while ( i < n_stu && strcmp(stu[i]._id, id_s))
        i++;

    if (i == n_stu) 
    {
        cout << "no found." << endl;
        system("pause");
        return;
    }

    cout << ("please input the ID of course you want to select: ");
    cin >> id_c;
    while ( j < n_cour && strcmp(cour[j].c_id(), id_c))
        j++;


    if (j == n_cour)
    {
        cout << "no found." << endl;
        system("pause");
        return;
    }

    if (cour[j].count >= 60)
    {
        cout << "student number full, select failed." << endl;
        system("pause");
    }
    else
    {
        if (cour[j].c_nature())
            if (stu[i]._num_compulsory < 2)
            {
                int c = 0;
                while (c < stu[i]._num_compulsory && strcmp(cour[j].id, stu[i]._cour_compulsory[c].id))
                    c++;

                if (c < stu[i]._num_compulsory)
                {
                    cout << "course repeat." << endl;
                    system("pause");
                    return;
                }
                stu[i]._cour_compulsory[stu[i]._num_compulsory] = cour[j];  
                stu[i]._num_compulsory++;
                cour[j].count++;
                Write_course(cour, n_cour);
                Write_stu(stu, n_stu);
                cout << "select succeed." << endl;
                system("pause");
            }
            else
            {
                cout << "class number upper limit, select failed." << endl;
                system("pause");
            }
        else
        {
            if (stu[i]._num_elective < 1)
            {
                int c = 0;
                while (c < stu[i]._num_elective && strcmp(cour[j].id, stu[i]._cour_elective[c].id))
                    c++;

                if (c < stu[i]._num_elective)
                {
                    cout << "course repeat." << endl;
                    system("pause");
                    return;
                }

                stu[i]._cour_elective[stu[i]._num_elective] = cour[j];
                stu[i]._num_elective++;
                cour[j].count++;
                Write_course(cour, n_cour);
                Write_stu(stu, n_stu);
                cout << "select succeed." << endl;
                system("pause");
            }
            else
            {
                cout << "class number upper limit, select failed." << endl;
                system("pause");
            }
        }
    }
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100

需要先从文件中读取到数据，然后需要输入学生id，确定身份，再输入你想选择的课程编号。如果找不到该学生或课程，就会打印no found.。找到之后，先判断的就是该课程的选课人数是否达到上限60人，如果达到，就会提示人数上限，选课失败，没达到，就进入下一环。接着判断所选择的课程类型，是必修，就判断该学生选择的必修课程数量是否达到上限，没有达到上限才会提示选课成功；是选修，就判断该学生选择的选修课数量是否达到上限，没有达到才会提示选课成功。

2.2.6退选模块设计

void Deselect(vector<Course>& cour, vector<Student>& stu)
{
    system("cls");
    int n_cour = Read_course(cour);
    int n_stu = Read_stu(stu);
    int i = 0;              // student
    int j = 0;              // course

    char id_c[20];          // course  
    char id_s[20];          // student                                                                               
    cout << "============ deselect system ============" << endl;
    cout << "please input the ID of student: ";
    cin >> id_s;
    while (i < n_stu && strcmp(stu[i]._id, id_s))
        i++;

    if (i == n_stu)
    {
        cout << "no found." << endl;
        system("pause");
        return;
    }

    cout << ("please input the ID of course you want to deselect: ");
    cin >> id_c;
    while (j < n_cour && strcmp(cour[j].c_id(), id_c))
        j++;

    if (j == n_cour)
    {
        cout << "no found." << endl;
        system("pause");
        return;
    }
    
    if (stu[i]._num_compulsory)
    {
        int c = stu[i]._num_compulsory - 1;
        while (c >= 0)
        {
            if (!strcmp(stu[i]._cour_compulsory[c].id, id_c))
            {
                cour[j].count--;
                stu[i]._num_compulsory--;
                strcpy(stu[i]._cour_compulsory[c].id, "None");
                strcpy(stu[i]._cour_compulsory[c].name, "None");

                // 重新排序
                for (; c < stu[i]._num_compulsory; c++)
                    swap(stu[i]._cour_compulsory[c], stu[i]._cour_compulsory[c + 1]);

                Write_stu(stu, n_stu);
                Write_course(cour, n_cour);
                cout << "退选成功。" << endl;
                system("pause");
                return;
            }
            c--;
        }

        if (stu[i]._cour_elective)
        {
            int c = stu[i]._num_elective - 1;
            while (c >= 0)
            {
                if (!strcmp(stu[i]._cour_elective[c].id, id_c))
                {
                    cour[j].count--;
                    stu[i]._num_elective--;
                    strcpy(stu[i]._cour_elective[c].id, "None");
                    strcpy(stu[i]._cour_elective[c].name, "None");

                    for (; c < stu[i]._num_elective; c++)
                        swap(stu[i]._cour_elective[c], stu[i]._cour_elective[c + 1]);

                    Write_stu(stu, n_stu);
                    Write_course(cour, n_cour);
                    cout << "退选成功。" << endl;
                    system("pause");
                    return;
                }
                c--;
            }
            cout << "你并未选择该课程。" << endl;
            system("pause");
            return;
        }
    }
    
    if (stu[i]._cour_elective)
    {
    	int c = stu[i]._num_elective - 1;
   	    while (c >= 0)
 	    {
   		    if (!strcmp(stu[i]._cour_elective[c].id, id_c))
            {
       		     cour[j].count--;
                stu[i]._num_elective--;
                strcpy(stu[i]._cour_elective[c].id, "None");
                strcpy(stu[i]._cour_elective[c].name, "None");

                for (; c < stu[i]._num_elective; c++)
                swap(stu[i]._cour_elective[c], stu[i]._cour_elective[c + 1]);

                Write_stu(stu, n_stu);
                Write_course(cour, n_cour);
                cout << "退选成功。" << endl;
                system("pause");
                return;
       		}
       		c--;
     	}
       	cout << "你并未选择该课程。" << endl;
       	system("pause");
       	return;
  	}
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117

退选功能实现的前半部分和选课功能类似，先从文件中读取信息，输入学生id，确定身份，再输入想退选的课程id，确定要退选的课程是否存在。如果存在，接着判断该学生是否选择了该课程，只有选择了该课程，才会提示退选成功，否则提示退选失败。

退选功能中有一个细节需要尤其注意，就是每回退选课程，都需要对学生信息中的课程数组重新排序，相当于在学生信息的课程数组中，删除了这个课程。为什么要排序呢？因为我在实现选课和退选功能的时候，都是用学生成员变量中的_num_compulsory和_num_elective来做课程数组的下标的，如果不进行重新排序，会导致逻辑混乱。举个例子，现在有一个学生选了两门必修课，_cour_compulsory[0]存的是第一门课，_cour_compulsory[1]存的是第二门课，那_num_compulsory毫无疑问就是2。现在我们退选第一门课，也就是将_cour_compulsory[0]的数据改成默认值，id是None，name也是None，再对_num_compulsory减减。现在没有进行排序，此时_num_compulsory为1，再对该学生进行选课操作时，执行代码stu[i]._cour_compulsory[stu[i]._num_compulsory] = cour[j]; 会将_cour_compulsory[1]中的有效数据覆盖，而_cour_compulsory[0]中仍然是无效数据，出现逻辑错误。所以我们需要对数组重新排序，让_cour_compulsory[1]的先值给到_cour_compulsory[0]。

3.完整代码

#define _CRT_SECURE_NO_WARNINGS

#include<iostream>
#include<fstream>
#include<vector>
#include<string.h>  
#include<stdlib.h>
using namespace std;

int flag = 0;                   // default is student

class Course 
{
public:
    friend void Input_course(vector<Course>& cour);
    friend void Delete_course(vector<Course>& cour);
    friend void Modify_course(vector<Course>& cour);
    friend void Lookup_course(vector<Course>& cour);
    friend void Show_course(vector<Course>& cour);
    friend void Add_course(vector<Course>& cour);                                                                       
    friend int Read_course(vector<Course>& cour);
    friend void Write_course(vector<Course>& cour, int n);

    const char* c_id() { return id; }
    const char* c_name() { return name; }
    const bool c_nature() { return nature; }

    Course()
        : id("None")
        , name("None")
        , count(0)
    {}

public:
    char id[20];
    char name[20];
private:
    bool nature;            // 0 indicates elective and 1 indicates compulsory
    int hour;               // class time                                                                             
    int credir;             // credit
public:
    int count;              // count of student 0-60
};

class Student
{
public:
    friend void Input_stu(vector<Student>& stu);
    friend void Delete_stu(vector<Student>& stu);
    friend void Modify_stu(vector<Student>& stu);
    friend void Lookup_stu(vector<Student>& stu);
    friend void Add_stu(vector<Student>& stu);
    friend void Show_stu(vector<Student>& stu);
    friend int Read_stu(vector<Student>& stu);
    friend void Write_stu(vector<Student>& stu, int n);

    friend void Select(vector<Course>& cour, vector<Student>& stu);
    friend void Deselect(vector<Course>& cour, vector<Student>& stu);
public:
    char _id[20];
    char _class[20];
    char _name[20];
    Course _cour_compulsory[2];
    Course _cour_elective[1];
    int _num_compulsory = 0;
    int _num_elective = 0;
};

vector<Course> cour;
vector<Student> stu;

// ========================================== Course ==================================================== //

void Write_course(vector<Course>& cour, int n)
{
    fstream myfile;
    myfile.open("course.txt", ios::out | ios::binary);
    if (!myfile)
    {
        cout << "ERROR!course.txt can't open." << endl;
        abort();
    }

    myfile << n << endl << endl;
    for (int i = 0; i < n; i++)
    {
        myfile << cour[i].id << "\t" << cour[i].name << "\t"
            << cour[i].nature << "\t" << cour[i].hour << "\t"
            << cour[i].credir << "\t" << cour[i].count << endl;
    }
    myfile.close();
}

int Read_course(vector<Course>& cour)
{
    cour.clear();                           // clear
    fstream myfile;
    myfile.open("course.txt", ios::in | ios::binary);
    if (!myfile)
    {
        cout << "ERROR!course.txt can't open." << endl;
        abort();
    }

    int n;                                  // count of course
    myfile.seekg(0);
    myfile >> n;

    Course temp;
    for (int i = 0; i < n; i++)
    {
        myfile >> temp.id >> temp.name >> temp.nature
            >> temp.hour >> temp.credir >> temp.count;
        cour.push_back(temp);           // push_back
    }

    myfile.close();
    return n;
}

void Input_course(vector<Course>& cour)
{
    system("cls");
    cour.clear();
    int i = 0;
    char sign = '0';
    Course temp;

    cout << "=============== Please input the massage ===============" << endl;
    while (sign != 'n' && sign != 'N')
    {
    loop:
        cout << "ID: ";
        cin >> temp.id;

        int c = 0;
        while (c < i)
        {
            c++;
            if (!strcmp(temp.id, cour[i - c].id))
            {
                cout << "ID repeat, please input again." << endl;
                goto loop;
            }
        }

        cout << "name of course: ";
        cin >> temp.name;
        cout << "elective or compilsory(0 or 1): ";
        cin >> temp.nature;
        cout << "class hour: ";
        cin >> temp.hour;
        cout << "credir: ";
        cin >> temp.credir;
        temp.count = 0;                 // the default is 0

        cour.push_back(temp);           // push_back

        cout << "whether continue(y or n): ";
        cin >> sign;
        i++;
    }

    Write_course(cour, i);                  // save
}

void Delete_course(vector<Course>& cour)
{
    system("cls");
    int n = Read_course(cour);
    int i = 0;
    char id[20];
    cout << "=============== Delete the message of course ===============" << endl;
    cout << "please input the ID of course which you want to delete: ";
    cin >> id;
    while (i < n && strcmp(id, cour[i].id))
        i++;

    if (i == n)
    {
        cout << "no fount." << endl;
        system("pause");
        return;
    }
    else
    {
        if (cour[i].count)
        {
            cout << "所选人数不为零，请联系所有学生退课后，再修改课程信息。" << endl;
            system("pause");
            return;
        }
    }

    for (int j = i; j < n - 1; j++)
        swap(cour[j], cour[j + 1]);

    // save
    char sign;
    cout << "whether delete(y or n): ";
    cin >> sign;
    if (sign != 'n' && sign != 'N')
    {
        cour.erase(cour.end() - 1);
        Write_course(cour, n - 1);
        cout << "=============== Delete succeed ===============" << endl;
    }
}

void Modify_course(vector<Course>& cour)
{
    system("cls");
    int n = Read_course(cour);                      // count of course
    char id[20];
    int i = 0;

    cout << "=============== Modify course ===============" << endl;
    cout << "input the ID of course you want to modify: ";
    cin >> id;
    while ( i < n && strcmp(id, cour[i].id))        // i < n 要提前判断
        i++;

    if (i == n)
    {
        cout << "no found." << endl;
        system("pause");
        return;
    }
    else
    {
        if (cour[i].count)
        {
            cout << "所选人数不为零，请联系所有学生退课后，再修改课程信息。" << endl;
            system("pause");
            return;
        }
    }

    cout << "----------------------------------------------------" << endl;
    cout << "ID" << "\t" << "name" << "\t" << "nature" << "\t"
        << "hour" << "\t" << "credir" << "\t" << "count" << endl;
    cout << "----------------------------------------------------" << endl;
    cout << cour[i].id << "\t" << cour[i].name << "\t" << cour[i].nature << "\t"
        << cour[i].hour << "\t" << cour[i].credir << "\t" << cour[i].count << endl;

    cout << "please reenter the message of course." << endl;
    cout << "name of course: ";
    cin >> cour[i].name;
    cout << "elective or compilsory(0 or 1): ";
    cin >> cour[i].nature;
    cout << "class hour: ";
    cin >> cour[i].hour;
    cout << "credir: ";
    cin >> cour[i].credir;

    // save
    char sign;
    cout << "whether save the data(y or n): ";
    cin >> sign;
    if (sign != 'n' && sign != 'N')
    {
        Write_course(cour, n);
        cout << "=============== Modify succeed ===============" << endl;
        system("pause");
    }
}

void Lookup_course(vector<Course>& cour)
{
    system("cls");
    int n = Read_course(cour);
    int i = 0;
    char id[20];

    cout << "=============== Lookup the course ===============" << endl;
    cout << "please input the course ID you want to seek: ";
    cin >> id;

    while (i < n && strcmp(id, cour[i].id))
        i++;

    if (i == n)
    {
        cout << "no found." << endl;
    }
    else
    {
        cout << "---------------------------------------------" << endl;
        cout << "ID: " << cour[i].id << endl;
        cout << "name: " << cour[i].name << endl;
        cout << "nature: " << (cour[i].nature ? "compulsory" : "elective") << endl;
        cout << "class hour: " << cour[i].hour << endl;
        cout << "credir: " << cour[i].credir << endl;
        cout << "student count: " << cour[i].count << endl;
    }
    system("pause");
}

void Show_course(vector<Course>& cour)
{
    system("cls");
    int n = Read_course(cour);

    cout << "================ display all course ================" << endl;
    cout << "----------------------------------------------------" << endl;
    cout << "ID" << "\t" << "name" << "\t" << "nature" << "\t"
        << "hour" << "\t" << "credir" << "\t" << "count" << endl;

    cout << "----------------------------------------------------" << endl;
    for (int i = 0; i < n; i++)
    {
        cout << cour[i].id << "\t" << cour[i].name << "\t" << cour[i].nature << "\t" << cour[i].hour << "\t" << cour[i].credir << "\t" << cour[i].count << endl;
    }
    system("pause");
}

void Add_course(vector<Course>& cour)
{
    system("cls");
    int n = Read_course(cour);
    char sign = '0';
    Course temp;

    cout << "=============== add course ===============" << endl;
    while (sign != 'n' && sign != 'N')
    {
    loop:
        cout << "ID: ";
        cin >> temp.id;
        int c = 0;
        while (c < n)
        {
            c++;
            if (!strcmp(temp.id, cour[n - c].id))
            {
                cout << "ID repeat, please input again." << endl;
                goto loop;
            }
        }

        cout << "name of course: ";
        cin >> temp.name;
        cout << "elective or compulsory(0 or 1): ";
        cin >> temp.nature;
        cout << "class hour: ";
        cin >> temp.hour;
        cout << "credir: ";
        cin >> temp.credir;
        temp.count = 0;

        n++;

        cour.push_back(temp);

        cout << "whether continue(y or n): ";
        cin >> sign;
    }

    // save
    Write_course(cour, n);
}

// ============================================ student ============================================== //

void Write_stu(vector<Student>& stu, int n)
{
    fstream myfile;
    myfile.open("student.txt", ios::out | ios::binary);
    if (!myfile)
    {
        cout << "ERROR! student.txt can't open!" << endl;
        abort();
    }

    myfile << n << endl << endl;
    for (int i = 0; i < n; i++)
    {
        myfile << stu[i]._id << "\t" << stu[i]._class << "\t"
            << stu[i]._name << "\t" 
            << stu[i]._cour_compulsory[0].c_id()   << "\t"
            << stu[i]._cour_compulsory[0].c_name() << "\t"
            << stu[i]._cour_compulsory[1].c_id()   << "\t"
            << stu[i]._cour_compulsory[1].c_name() << "\t"
            << stu[i]._cour_elective[0].c_id()     << "\t"
            << stu[i]._cour_elective[0].c_name()   << "\t"
            << stu[i]._num_compulsory << "\t" << stu[i]._num_elective << endl;
    }

    myfile.close();
}

int Read_stu(vector<Student>& stu)
{
    stu.clear();                            // clear
    fstream myfile;
    myfile.open("student.txt", ios::in | ios::binary);
    if (!myfile)
    {
        cout << "ERROR! student.txt can't open!" << endl;
        abort();
    }

    int n;
    myfile.seekg(0);
    myfile >> n;

    Student temp;

    for (int i = 0; i < n; i++)
    {
        myfile >> temp._id >> temp._class
            >> temp._name
            >> temp._cour_compulsory[0].id
            >> temp._cour_compulsory[0].name
            >> temp._cour_compulsory[1].id
            >> temp._cour_compulsory[1].name
            >> temp._cour_elective[0].id
            >> temp._cour_elective[0].name
            >> temp._num_compulsory >> temp._num_elective;
        stu.push_back(temp);            // push_back
    }

    myfile.close();
    return n;
}

void Input_stu(vector<Student>& stu)
{
    system("cls");
    stu.clear();
    int i = 0;
    char sign = '\0';
    Student temp;

    cout << "============ please input the message ============" << endl;
    while (sign != 'n' && sign != 'N')
    {
    loop:
        cout << "student ID: ";
        cin >> temp._id;

        int c = 0;
        while (c < i)
        {
            c++;
            if (!strcmp(temp._id, stu[i - c]._id))
            {
                cout << "ID repeat, please input again." << endl;
                goto loop;
            }
        }

        cout << "name: ";
        cin >> temp._name;
        cout << "class: ";
        cin >> temp._class;

        stu.push_back(temp);            // push_back
        cout << "whether continue(y or n): ";
        cin >> sign;
        i++;
    }
    Write_stu(stu, i);
}

void Delete_stu(vector<Student>& stu)
{
    system("cls");
    int n = Read_stu(stu);
    int m = Read_course(cour);  // number of course
    int i = 0;
    char id[20];

    cout << "============ delete student ============" << endl;
    cout << "please input the ID of student who you want to delete: ";
    cin >> id;

    while (i < n && strcmp(id, stu[i]._id))
        i++;

    if (i == n)
    {
        cout << "no fount." << endl;
        system("pause");
        return;
    }

    if (stu[i]._num_compulsory)
    {
        while (stu[i]._num_compulsory > 0)
        {
            stu[i]._num_compulsory--;

            int c = 0;
            while (c < m)
            {
                if (!strcmp(stu[i]._cour_compulsory[stu[i]._num_compulsory].id, cour[c].id))
                {
                    cour[c].count--;
                    break;
                }
                c++;
            }
        }
    }
    else if (stu[i]._num_elective)
    {
        while (stu[i]._num_elective > 0)
        {
            stu[i]._num_elective--;

            int c = 0;
            while (c < m)
            {
                if (!strcmp(stu[i]._cour_elective[stu[i]._num_elective].id, cour[c].id))
                {
                    cour[c].count--;
                    break;
                }
                c++;
            }
        }
    }

    for (int j = i; j < n - 1; j++)
        swap(stu[j], stu[j + 1]);

    // save
    char sign;
    cout << "whether delete(y or n): ";
    cin >> sign;
    if (sign != 'n' && sign != 'N')
    {
        stu.erase(stu.end() - 1);
        Write_stu(stu, n - 1);
        Write_course(cour, m);
        cout << "============ delete succeed ============" << endl;
        system("pause");
    }
}

void Modify_stu(vector<Student>& stu)
{
    system("cls");
    int n = Read_stu(stu);
    char id[20];
    int i = 0;

    cout << "============ Modify the message of student ============" << endl;
    cout << "please input the ID of student who you want to modify: ";
    cin >> id;

    while (i < n && strcmp(id, stu[i]._id))
        i++;

    if (i == n)
    {
        cout << "no found." << endl;
        system("pause");
        return;
    }

    cout << "-------------------------------------------------------" << endl;
    cout << "ID: " << stu[i]._id << endl;
    cout << "class: " << stu[i]._class << endl;
    cout << "name: " << stu[i]._name << endl;
    cout << "-------------------------------------------------------" << endl;

    cout << "please reenter the message." << endl;
    cout << "class: ";
    cin >> stu[i]._class;
    cout << "name: ";
    cin >> stu[i]._name;

    // save
    char sign;
    cout << "whether save the data(y or n): ";
    cin >> sign;
    if (sign != 'n' && sign != 'N')
    {
        cout << "modify succeed." << endl;                                                                                    
        Write_stu(stu, n);
        system("pause");
    }
}

void Lookup_stu(vector<Student>& stu)
{
    system("cls");    
    int n = Read_stu(stu);
    Read_course(cour);
    int i = 0;
    char id[20];  
    
    cout << "============ Lookup the score of student ============" << endl;    
    cout << "please input the ID of student you want to seek: ";
    cin >> id;

    while (i < n && strcmp(id, stu[i]._id))
        i++;
    
    if (i == n)
    {
        cout << "no found." << endl;
    }
    else
    { 
        cout << "ID: " << stu[i]._id << endl;
        cout << "class: " << stu[i]._class << endl;
        cout << "name: " << stu[i]._name << endl;
        cout << "compulsory: " << (!strcmp(stu[i]._cour_compulsory[0].id, "None") ? "None" : stu[i]._cour_compulsory[0].c_name())
             << " " 
             << (!strcmp(stu[i]._cour_compulsory[1].id, "None") ? "None" : stu[i]._cour_compulsory[1].c_name()) 
             << endl;
        cout << "elective: " 
             << (!strcmp(stu[i]._cour_elective[0].id, "None") ? "None" : stu[i]._cour_elective[0].c_name()) 
             << endl;
    }
    system("pause");
}

void Add_stu(vector<Student>& stu) 
{
    system("cls");
    int n = Read_stu(stu);
    char sign = '0';
    Student temp;

    cout << "============ add student ============" << endl;
    while (sign != 'n' && sign != 'N')
    {
    loop:
        cout << "student ID: ";
        cin >> temp._id;

        int c = 0;
        while (c < n)
        {
            c++;
            if (!strcmp(temp._id, stu[n - c]._id))
            {
                cout << "ID repeat, please input again." << endl;
                goto loop;
            }
        }

        cout << "class: ";
        cin >> temp._class;
        cout << "name: ";
        cin >> temp._name;
        n++;

        stu.push_back(temp);                    // push_back

        cout << "whether continue(y or n): ";
        cin >> sign;
    }

    // save
    Write_stu(stu, n);
}

void Show_stu(vector<Student>& stu)
{   
    system("cls");                                                                                                        
    int n = Read_stu(stu);

    cout << "============================ diplay all student ==========================" << endl;
    cout << "ID" << "\t" << "class" << "\t" << "name" << "\t" 
         << "compulsory" << "\t\t" << "elective" << endl;   
    cout << "--------------------------------------------------------------------------" << endl;
    for (int i = 0; i < n; i++)
    {
        cout << stu[i]._id << "\t" << stu[i]._class << "\t" << stu[i]._name << "\t" 
            << (!strcmp(stu[i]._cour_compulsory[0].id, "None") ? "None" : stu[i]._cour_compulsory[0].name)
            << " "
            << (!strcmp(stu[i]._cour_compulsory[1].id, "None") ? "None" : stu[i]._cour_compulsory[1].c_name())
            << "\t"
            << (!strcmp(stu[i]._cour_elective[0].id, "None") ? "None" : stu[i]._cour_elective[0].c_name()) 
            << endl;
    }

    system("pause");
}

void Select(vector<Course>& cour, vector<Student>& stu) 
{
    system("cls");
    int n_cour = Read_course(cour);
    int n_stu = Read_stu(stu);   
    int i = 0;              // student
    int j = 0;              // course

    char id_c[20];          // course  
    char id_s[20];          // student                                                                               
    cout << "============ select system ============" << endl;
    cout << "please input the ID of student: ";
    cin >> id_s;
    while ( i < n_stu && strcmp(stu[i]._id, id_s))
        i++;

    if (i == n_stu) 
    {
        cout << "no found." << endl;
        system("pause");
        return;
    }

    cout << ("please input the ID of course you want to select: ");
    cin >> id_c;
    while ( j < n_cour && strcmp(cour[j].c_id(), id_c))
        j++;

    // cout << cour[j].id << endl;

    if (j == n_cour)
    {
        cout << "no found." << endl;
        system("pause");
        return;
    }

    if (cour[j].count >= 60)
    {
        cout << "student number full, select failed." << endl;
        system("pause");
    }
    else
    {
        if (cour[j].c_nature())
            if (stu[i]._num_compulsory < 2)
            {
                int c = 0;
                while (c < stu[i]._num_compulsory && strcmp(cour[j].id, stu[i]._cour_compulsory[c].id))
                    c++;

                if (c < stu[i]._num_compulsory)
                {
                    cout << "course repeat." << endl;
                    system("pause");
                    return;
                }
                stu[i]._cour_compulsory[stu[i]._num_compulsory] = cour[j];  
                // cout << stu[i]._cour_compulsory[stu[i]._num_compulsory].id << endl;
                // cout << stu[i]._cour_compulsory[stu[i]._num_compulsory].c_name() << endl;
                stu[i]._num_compulsory++;
                cour[j].count++;
                Write_course(cour, n_cour);
                Write_stu(stu, n_stu);
                // cout << stu[i]._cour_compulsory[stu[i]._num_compulsory].id << endl;
                cout << "select succeed." << endl;
                system("pause");
            }
            else
            {
                cout << "class number upper limit, select failed." << endl;
                system("pause");
            }
        else
        {
            if (stu[i]._num_elective < 1)
            {
                int c = 0;
                while (c < stu[i]._num_elective && strcmp(cour[j].id, stu[i]._cour_elective[c].id))
                    c++;

                if (c < stu[i]._num_elective)
                {
                    cout << "course repeat." << endl;
                    system("pause");
                    return;
                }

                stu[i]._cour_elective[stu[i]._num_elective] = cour[j];
                stu[i]._num_elective++;
                cour[j].count++;
                Write_course(cour, n_cour);
                Write_stu(stu, n_stu);
                cout << "select succeed." << endl;
                system("pause");
            }
            else
            {
                cout << "class number upper limit, select failed." << endl;
                system("pause");
            }
        }
    }
}

void Deselect(vector<Course>& cour, vector<Student>& stu)
{
    system("cls");
    int n_cour = Read_course(cour);
    int n_stu = Read_stu(stu);
    int i = 0;              // student
    int j = 0;              // course

    char id_c[20];          // course  
    char id_s[20];          // student                                                                               
    cout << "============ deselect system ============" << endl;
    cout << "please input the ID of student: ";
    cin >> id_s;
    while (i < n_stu && strcmp(stu[i]._id, id_s))
        i++;

    if (i == n_stu)
    {
        cout << "no found." << endl;
        system("pause");
        return;
    }

    cout << ("please input the ID of course you want to deselect: ");
    cin >> id_c;
    while (j < n_cour && strcmp(cour[j].c_id(), id_c))
        j++;

    if (j == n_cour)
    {
        cout << "no found." << endl;
        system("pause");
        return;
    }
    
    if (stu[i]._num_compulsory)
    {
        int c = stu[i]._num_compulsory - 1;
        while (c >= 0)
        {
            if (!strcmp(stu[i]._cour_compulsory[c].id, id_c))
            {
                cour[j].count--;
                stu[i]._num_compulsory--;
                strcpy(stu[i]._cour_compulsory[c].id, "None");
                strcpy(stu[i]._cour_compulsory[c].name, "None");

                // 重新排序
                for (; c < stu[i]._num_compulsory; c++)
                    swap(stu[i]._cour_compulsory[c], stu[i]._cour_compulsory[c + 1]);

                Write_stu(stu, n_stu);
                Write_course(cour, n_cour);
                cout << "退选成功。" << endl;
                system("pause");
                return;
            }
            c--;
        }

        if (stu[i]._cour_elective)
        {
            int c = stu[i]._num_elective - 1;
            while (c >= 0)
            {
                if (!strcmp(stu[i]._cour_elective[c].id, id_c))
                {
                    cour[j].count--;
                    stu[i]._num_elective--;
                    strcpy(stu[i]._cour_elective[c].id, "None");
                    strcpy(stu[i]._cour_elective[c].name, "None");

                    for (; c < stu[i]._num_elective; c++)
                        swap(stu[i]._cour_elective[c], stu[i]._cour_elective[c + 1]);

                    Write_stu(stu, n_stu);
                    Write_course(cour, n_cour);
                    cout << "退选成功。" << endl;
                    system("pause");
                    return;
                }
                c--;
            }
            cout << "你并未选择该课程。" << endl;
            system("pause");
            return;
        }
    }
    
    if (stu[i]._cour_elective)
    {
    	int c = stu[i]._num_elective - 1;
   	    while (c >= 0)
 	    {
   		    if (!strcmp(stu[i]._cour_elective[c].id, id_c))
            {
       		     cour[j].count--;
                stu[i]._num_elective--;
                strcpy(stu[i]._cour_elective[c].id, "None");
                strcpy(stu[i]._cour_elective[c].name, "None");

                for (; c < stu[i]._num_elective; c++)
                swap(stu[i]._cour_elective[c], stu[i]._cour_elective[c + 1]);

                Write_stu(stu, n_stu);
                Write_course(cour, n_cour);
                cout << "退选成功。" << endl;
                system("pause");
                return;
       		}
       		c--;
     	}
       	cout << "你并未选择该课程。" << endl;
       	system("pause");
       	return;
  	}
}

// =========================================== menu ========================================== //

int choose_user()
{
loop:
    system("cls");
    int c = 0;
    cout << "=================================================================" << endl;
    cout << "-------------- welcome to course selection system ---------------" << endl;
    cout << "please choose your identity, admin or student(1 or 2)(input 0 to exit): ";
    cin >> c;

    char passwd[20];
    if (c == 1)
    {
        cout << "please input password: ";
        cin >> passwd;
        if (!strcmp(passwd, "123456"))
        {
            flag = 1;
            cout << "log on succeed." << endl;
            system("pause");
        }
        else
        {
            cout << "password error." << endl;
            system("pause");
            goto loop;
        }
    }
    else
        flag = 0;

    if (c < 0 || c > 2)
    {
        cout << "please input 0-2." << endl;
        system("pause");
        goto loop;
    }

    return c;
}

void menu_course()
{
    int c = 0;
    while (1)
    {
        system("cls");
        cout << "============ menu of course ============" << endl;
        cout << "               1. input                 " << endl;
        cout << "               2. delete                " << endl;
        cout << "               3. modify                " << endl;
        cout << "               4. lookup                " << endl;
        cout << "               5. add                   " << endl;
        cout << "               6. show all              " << endl;
        cout << "               0. return                " << endl;
        cout << "----------------------------------------" << endl;
        cout << "please choose your operation(0-6): ";
        cin >> c;
        switch (c)
        {
        case 1:
            if (flag)
                Input_course(cour);
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;
        case 2:
            if (flag)
                Delete_course(cour);
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;
        case 3:
            if (flag)
                Modify_course(cour);
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;
        case 4:
            Lookup_course(cour);
            break;
        case 5:
            if (flag)
                Add_course(cour);
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;
        case 6:
            Show_course(cour);
            break;
        case 0:
            cout << "------------ return succeed ------------" << endl;
            system("pause");
            return;
        default:
            cout << "please input 0-6." << endl;
            system("pause");
            break;
        }
    }
}

void menu_student()
{
    int c = 0;
    while (1)
    {
        system("cls");
        cout << "============ menu of student ============" << endl;
        cout << "               1. input                 " << endl;                                                        
        cout << "               2. delete                " << endl;                                                         
        cout << "               3. modify                " << endl;                                                          
        cout << "               4. lookup                " << endl;                                                           
        cout << "               5. add                   " << endl;
        cout << "               6. show all              " << endl;
        cout << "               7. select course         " << endl;
        cout << "               8. deselect              " << endl;
        cout << "               0. return                " << endl;
        cout << "----------------------------------------" << endl;                                                          
        cout << "please choose your operation(0-6): ";
        cin >> c;
        switch (c) 
        {
        case 1:                                                                                                                        
            if (flag)
                Input_stu(stu);
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;                                                                                                         
        case 2:
            if (flag)                                                                                                                   
                Delete_stu(stu);                                                                                                 
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;                                                                                                         
        case 3:                                                                                                                       
            if (flag)                                                                                                             
                Modify_stu(stu);                                                                                           
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;                                                                                                       
        case 4:                                                                                                                     
            Lookup_stu(stu);                                                                                                   
            break;                                                                                                       
        case 5:                                                                                                                    
            if (flag)                                                                                                                      
                Add_stu(stu);                                                                                              
            else
            {
                cout << "request denied." << endl;
                system("pause");
            }
            break;                                                                                                      
        case 6:                                                                                                                   
            Show_stu(stu);                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
            break;
        case 7:
            Select(cour, stu);
            break;
        case 8:
            Deselect(cour, stu);
            break;
        case 0:
            cout << "------------ return succeed ------------" << endl;
            system("pause");
            return;
        default:
            cout << "please input 0-6." << endl;
            system("pause");
            break;
        }
    }
}

int menu_main()
{
    int c = 0;
    while (1)
    {
        system("cls");
        cout << "====================================================" << endl;
        cout << "               1. course message                    " << endl;
        cout << "               2. student message                   " << endl;
        cout << "               0. go back to higher-leve menu       " << endl;
        cout << "choose your operation: ";
        cin >> c;

        if (c < 0 || c > 2)
        {
            cout << "please input 0-2." << endl;
            system("pause");
        }
        else
            break;
    }

    return c;
}


// ============================================================================================================= //


int main()
{
    cour.reserve(100);
    stu.reserve(100);
    while (1)
    {
    loop:
        if (!choose_user())
        {
            cout << "=============== thank you for using ===============" << endl;
            return 0;
        }
        while (1)
        {
            switch (menu_main())
            {
            case 1:
                menu_course();
                break;
            case 2:
                menu_student();
                break;
            case 0:
                cout << "=============== return scceed ===============" << endl;
                system("pause");
                goto loop;
            default:
                cout << "please input 0-2." << endl;
                system("pause");
                break;
            }
        }
    }
    return 0;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169

大家可以自行复制运行。

4.总结与展望

4.1设计总结

本次课程设计是我第一次独自完成这样一个相对完整的项目，收获很多。但是我更想说一下本次设计中存在的不足。首先就是在最初设计课程类和学生类时，没有考虑的那么全面，导致出现了很多冗余的接口，和公有私有混着用的情况。其次就是，虽然是用C++写的，却没有把封装体现出来，使用了很多friend友元函数也破坏了类的封装效果。

4.2设计展望

接下来，我打算再优化一下这个系统，首先就是从友元函数入手，减少友元。我打算将增删改查都设计成成员函数，这样函数的命名也会方便很多。

然后就是将用到字符串的地方，全部使用string代替，可以避免使用很多C中的字符串操作函数。我还准备设计一下学生类和课程类的输入输出流重载，这样也能让代码量减少很多。

以上就是我对本次程序设计实习的设计展望。谢谢大家的支持！

声明：本文内容由网友自发贡献，不代表【wpsshop博客】立场，版权归原作者所有，本站不承担相应法律责任。如您发现有侵权的内容，请联系我们。转载请注明出处：https://www.wpsshop.cn/w/小惠珠哦/article/detail/791493