binary_search（）函数，要更深入的学习了解，关于某些控件没有返回值的问题，多加研究。
判断是否是素数
int main() { int i; int j; int count = 0; printf("请输入数字:"); scanf("%d", &i); for (j = 2; j <i; j++) { if (i%j == 0) count++; } if (count == 0) { printf("%d是素数\n", i); } else printf("%d不是素数\n", i); system("pause"); return 0; } 调用函数 int test(int i) { int j; int count = 0; for (j = 2; j < i; j++) { if (i%j == 0) { count++; } } if (count == 0) { return 0; } else return - 1; } int main() { int i; //int j; printf("请输入数字:"); scanf("%d", &i); int ret = test(i); if (ret == 0) { printf("%d是素数\n", i); } else { printf("%d不是素数\n", i); } system("pause"); return 0; } 判断闰年 int test(int y) { if (y % 4 == 0 && y % 100 != 0) { return 0; } else if (y % 400 == 0) { return 0; } else { return -1; } } int main() { int year = 0; int count = 0; printf("请输入年份："); scanf("%d", &year); int ret = test(year); if (ret == 0) { printf("%d是闰年\n", year); } else { printf("%d不是闰年\n", year); } system("pause"); return 0; } 只有一个主函数 的程序 int main() { int year = 0; printf("请输入年份："); scanf("%d", &year); if (year % 4 == 0 && year % 100 != 0) { printf("%d是闰年", year); } else if (year % 400 == 0) { printf("%d是闰年", year); } else { printf("%d不是闰年", year); } system("pause"); return 0; } 折半查找 int binary_search(int array[], int key,int left,int right) { /*int left = 0; int right = sizeof(array) / sizeof(array [0]) - 1;*/ /*int right = size - 1;*/ while (left <= right) { int mid = left + ((right - left) >> 1); if (key > array[mid]) { left = mid + 1; } else if (key < array[mid]) { right = mid - 1; } else { return mid; break;/*printf("此数字在数 组中，%d\n", mid);*/ } } return -1; /* break;*/ } int main() { int array[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 ,10}; int size = sizeof(array) /sizeof( array [0]); int key; printf("要查找的数字:"); scanf("%d", &key); int ret = binary_search(array,key,0,9); if (ret == -1) { /*printf("found!this is the %d\n", ret);*/ printf("no found!\n");\ } else { printf("found!this is the %d\n", ret); } system("pause"); return 0; } 调用函数参数值加1 #include<stdio.h> #include<Windows.h> int add(int n) { n++; return n; } int main() { int num = 0,ret = 0; int t = 0; int i; printf("调用次数：>"); scanf("%d", &t); for (i = 1; i <= t; i++) { ret += add(num); } printf("%d", ret); system("pause"); return 0; }