苏小红c语言第四版课后习题练习9.3--9.4_c语言程序设计苏小红第四版答案9.4

 9.3

   1 #include <stdio.h>
   2 void Swap(int *p, int *q){
   3     int t;
   4 
   5     t = *p;
   6     *p = *q;
   7     *q = t;
   8 }
   9 
  10 int main()
  11 {
  12     int a[5] = {1,2,3,4,5};
  13     int b[5] = {6,7,8,9,10};
  14     int i, j, k;
  15 
  16     for(i = 0; i < 5; i++){
  17         Swap(&a[i], &b[i]);
  18     }
  19     for(j = 0; j < 5; j++){
  20         printf("a[%d]= %d ", j,a[j]);
  21     }
  22 
  23     printf("\n");
  24 
  25     for(k = 0; k < 5; k++){
  26         printf("b[%d]= %d ", k, b[k]);
  27     }
  28     return 0;
  29 }

9.4

   1 #include <stdio.h>
   2 void Swap(int *p, int *q){
   3     int t;
   4 
   5     t = *p;
   6     *p = *q;
   7     *q = t;
   8 }
   9 
  10 int main()
  11 {
  12     int a[10];
  13     int i, j, k, l, b = 0, d = 0, max1, max2;
  14     int *p = a;
  15 
  16     for(i = 0; i < 10; i++){
  17         scanf("%d", &a[i]);
  18     }
  19 
  20     max1 = a[0];
  21     max2 = a[0];
  22 
  23     for(j = 1; j < 10; j++){
  24         if(max1 > a[j]){
  25             max1 = a[j];
  26             b = j;
  27         }
  28     }
  29 
  30     for(k = 1; k < 10; k++){
  31         if(max2 < a[k]){
  32             max2 = a[k];
  33             d = k;
  34         }
  35     }
  36 
  37     Swap(p+b,p+d);
  38 
  39     for(l = 0; l < 10; l++){
  40         printf("a[%d] = %d ", l, *(p+l));
  41     }
  42 
  43     return 0;
  44 
  45 }
  46 

 本体思路就是直接分别找到最大值以及最小值，并借此找到对应的下标，将最大值最小值的下标通过函数进行交换即可；

   1 #include <stdio.h>
   2 int Fun(const int arr1[], const int arr2[], const int year, const int month, const int day){
   3 
   4     int i, j, sum = 0;
   5 
   6     if((year%4==0&&year%100!=0)||(year%400==0)){
   7         for(i = 0; i < month-1; i++){
   8             sum+= arr1[i];
   9         }
  10     }else {
  11         for(j = 0; j < month-1; j++){
  12             sum+= arr2[j];
  13         }
  14     }
  15     return sum+day;
  16 
  17 }
  18 int main()
  19 {
  20     int year, month, day, d;
  21     int a[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
  22     int b[12] = {31,29,31,30,31,30,31,31,30,31,30,31};
  23 
  24     printf("请输入年月日：\n");
  25 
  26     scanf("%d %d %d", &year, &month, &day);
  27 
  28     d = Fun(b, a, year, month, day);
  29 
  30     printf("该日为 %d 年的 %d 天；\n", year, d);
  31 
  32     return 0;
  33 }
  34 

（题目中要求的函数没有输入数组，按要求可以把数组放到函数中在定义就可以） 

   1 #include <stdio.h>
   2 void Monthday(int year, int yearday, int *pmonth, int *pday){
   3     int k, l, m, sum = 0;;
   4     int a[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
   5     int b[12] = {31,29,31,30,31,30,31,31,30,31,30,31};
   6     if(year%4==0&&year%100!=0||year%400==0){
   7         for(k = 0; k < 12; k++){
   8             sum+= b[k];
   9             if(yearday >= sum&&yearday <= (sum+b[k+1])){
  10                 m = k+1;
  11                 break;
  12             }
  13         }
  14     }else {
  15         for(l = 0; l < 12; l++){
  16             sum+= a[l];
  17             if(yearday >= sum&&yearday <= (sum+a[l+1])){
  18                 m = l+1;
  19                 break;
  20             }
  21         }
  22     }
  23 
  24     printf("为该年的 %d 月 %d 日 \n", *(pmonth+m), *(pday+yearday-sum-1));
  25 
  26 
  27 }
  28 
  29 int main()
  30 {
  31     int year, yearday, i, j;
  32     int month[12], day[31];
  33     int *pmonth = month;
  34     int *pday = day;
  35 
  36     printf("请输入年份及日子：\n");
  37     scanf("%d %d", &year, &yearday);
  38 
  39     for(i = 0; i < 12; i++){
  40         *(pmonth+i) = i+1;
  41     }
  42     for(j = 0; j < 31; j++){
  43         *(pday+j) = j+1;
  44     }
  45 
  46     Monthday(year, yearday, pmonth, pday);
  47 
  48 
  49     return 0;
  50 }