也是会计算长方体啦

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int main()
{
    double a, b, c,bulk;
    printf("请输入3个小数用来作为长方体的3边长，宽，高:");
    scanf("%lf %lf %lf", &a, &b, &c);
    double area1 = a * b;
    double area2 = a * c;
    double area3 = b * c;
    printf("area1(a*b)=%.2lf\n", area1);
    printf("area2(a*c)=%.2lf\n", area2);
    printf("area3(b*c)=%.2lf\n", area3);
    printf("长方体的体积是%lf\n", a * b * c);