四则运算

图片：

代码：

#include<stdio.h>
#include<stdlib.h>

int main()
{
    int j=0;

    printf("请选择四则运算的法则：
");
    printf("1.加 2.减 3.乘 4.除
");
    int num;
    scanf("%d",&num);

    for(int i=0;i<400;i++){
        int a,b;
        a = rand()%100+1;
        b = rand()%100+1;

        if(num==1){
            printf("%d + %d =
",a,b);
            printf("答案:%d

",a+b);
        }
        else if(num==2){
            printf("%d - %d =
",a,b);
            printf("答案:%d

",a-b);
        }
        else if(num==3){
            printf("%d × %d =
",a,b);
            printf("答案:%d

",a*b);
        }
        else {
            printf("%d ÷ %d =
",a,b);
            printf("答案:%f

",a/b);
        }
    }
}