#include <stdio.h>

int main() { int a = 0; int b = 0; float c = 0; input: printf("请输入两个整数,要求大于等于0而且小于等于100\n"); scanf("%d %d", &a, &b); if ((a >= 0 && a <= 100) && (b >= 0 && b <= 100)) { c = (a * b) / 2; printf("该直角三角形的面积是:%.1f\n", c); } else { printf("输入错误，请重新输入\n"); } goto input; return 0; }