实数四舍五入

#define _CRT_SECURE_NO_WARNINGS#include<stdio.h>int main(){double db,sum=1.0;int i,n;printf("请输入要四舍五入的实数：");scanf("%lf", &db);printf("\n请输入要保留的位数：");scanf("%d", &n);for (i = 0;i < n;i++){sum = sum * 10;}if (db*sum < (int)(db*sum + 0.5))db = (int)(db*sum + 0.5) / sum;elsedb = (int)(db*sum) / sum;printf("\n四舍五入后的实数：%lf", db);system("pause");return 0;}