[数据结构-严蔚敏版]P71串的抽象数据类型的定义_串的抽象数据类型定义

代码如下:

#include <iostream>
#include <string>
using namespace std;

typedef struct
{
	char *ch;
	int length;
}String;


bool initString(String &s)
{
	s.ch = nullptr;
	s.length = 0;
	return true;
}

bool strAssign(String &s, const char *ch)
{
	int len = strlen(ch);
	s.ch = new char[len + 1];
	if (!s.ch) return false;
	for (int i = 0; i < len; i++)
	{
		s.ch[i] = ch[i];
	}
	s.ch[len] = '\0';
	s.length = len;
	return true;
}

bool strCopy(String &s, String t)
{
	if (!t.ch) return false;
	if (s.ch) delete[] s.ch;
	int len = strlen(t.ch);
	s.ch = new char[len + 1];
	for (int i = 0; i < len; i++)
	{
		s.ch[i] = t.ch[i];
	}
	s.ch[len] = '\0';
	s.length = len;
	return true;
}

bool strEmpty(String s)
{
	if (s.ch && s.length == 0) return true;
	return false;
}

bool strCompare(String s, String ss)
{
	if (!s.ch) return false;
	if (!ss.ch) return false;
	for (int i = 0; i < s.length && i < ss.length; i++)
	{
		if (s.ch[i] != ss.ch[i])
		{
			return s.ch[i] - ss.ch[i];
		}
	}
	return s.length - ss.length;
}

int strLength(String s)
{
	return s.length;
}

bool clearString(String &s)
{
	s.length = 0;
	return true;
}


bool concatString(String &s, String s1, String s2)
{
	if (s.ch) delete[] s.ch;
	int len1 = s1.length;
	int len2 = s2.length;
	int len3 = len1 + len2;
	s.ch = new char[len3 + 1];
	for (int i = 0; i < len1; i++)
	{
		s.ch[i] = s1.ch[i];
	}
	for (int i = len1; i < len3; i++)
	{
		s.ch[i] = s2.ch[i];
	}
	s.ch[len3] = '\0';
	s.length = len3;
	return true;
}


bool subString(String &sub, String s, int pos, int len)
{
	if (!s.ch) return false;
	if (pos <1 || pos > s.length || len < 0 || len > s.length - pos + 1) return false;
	if (sub.ch) delete[] sub.ch;
	if (!len)
	{
		sub.ch = nullptr;
		sub.length = 0;
	}
	else
	{
		sub.ch = new char[len + 1];
		for (int i = 0; i < len; i++)
		{
			sub.ch[i] = s.ch[pos - 1 + i];
		}
		sub.ch[len] = '\0';
		sub.length = len;
	}
	return true;
}

int indexString(String s, String ss, int pos)
{
	if (pos > 0)
	{
		int n = s.length;
		int m = ss.length;
		int i = pos;
		String sub;
		initString(sub);
		while (i <= n - m + 1)
		{
			subString(sub, s, i, m);
			if (strCompare(sub, ss) != 0) ++i;
			else return i;
		}
	}
	return false;
}

bool strInsert(String &s, int pos, String t)
{
	if (t.ch && s.ch)
	{
		int len1 = t.length;
		int len2 = s.length;
		int len3 = len1 + len2;
		char *p = new char[len3 + 1];
		if (!p) return false;
		for (int i = 0; i < pos - 1 && i < len3; i++)
		{
			p[i] = s.ch[i];
		}
		for (int i = 0; i < len1 && pos - 1 + i; i++)
		{
			p[pos - 1 + i] = t.ch[i];
		}
		for (int i = 0; i < len3 - pos + 1 && pos + len1 - 1 + i < len3; i++)//pos + len1 - 1 + i < len3,防止数组越界，导致无法成功释放内存(数组越界以后，delete无法成功释放内存)
		{
			p[pos + len1 - 1 + i] = s.ch[pos - 1 + i];
		}
		p[len3] = '\0';
		delete[] s.ch;
		s.ch = nullptr;
		s.ch = p;
		s.length = len3;
		return true;
	}
	return false;
}

bool strDelete(String &s, int pos, int len)
{
	if (pos >= s.length) return false;
	if (pos + len >= s.length)
	{
		s.length = len;
		s.ch[len] = '\0';
	}
	else
	{
		int start = pos + len - 1;
		while (start <= s.length)
		{
			s.ch[pos - 1] = s.ch[start];
			++start;
			++pos;
		}

		s.length -= len;
	}
	return  true;
}


bool replaceString(String &s, String t, String v)
{
	int len_s = s.length;
	int len_t = t.length;
	int len_v = v.length;
	int j = 1;
	String sub;
	initString(sub);
	while (len_s - j + 1 >= len_t)
	{
		subString(sub, s, j, len_t);
		if (strCompare(sub, t) == 0)
		{
			strDelete(s, j, len_t);
			strInsert(s, j, v);
			j += len_v;
			s.length = s.length + len_v - len_t;
			len_s = s.length;
		}
		else
		{
			j++;
		}
	}
	return true;
}




bool destroyString(String &s)
{
	if (s.ch)
	{
		delete[]s.ch;
		s.length = 0;
	}
	return true;
}


int main()
{
	const char *ch = "dasfas";
	String s1;
	const char *ch1 = "dadas";
	String s2;
	const char *ch2 = "as";
	String s3;
	strAssign(s3, ch2);
	strAssign(s2, ch1);
	strAssign(s1, ch);
	strInsert(s1, 4, s2);
	strDelete(s1, 4, 5);
	cout << s1.ch << endl;
	cout << s2.ch << endl;
	replaceString(s1, s3, s2);
	cout << s1.ch << endl;
	String s4;
	initString(s4);
	strCopy(s4, s1);
	cout << s4.ch << endl;
	return 0;
}


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