#include<stdio.h>
#define PI 3.14
main()
{
float r,s1,s2,v;
printf("请输入半径 r=?");
scanf("%f",&r);
s1=PI*r*r;/* area of acircle */
s2=2*PI*r;/* circumference */
v=4.0*3.0*PI*r*r*r;/* volume */
printf("\n Area=%.2f,circumference=%.2f,volume=%.2f\n",s1,s2,v);
return 0;
}

我怕我C语音作业交不上去，机房又没有QQ之类的东西。。。

main()
{
int h,a,s;
printf("请输入三角形的高和底，并用空格隔开\n");
scanf("%d %d",&h,a);
s=a*h/2;
printf("s=%d*%d/2=%d\n",h,a,s);
return 0;
}

# include <stdio.h>
main()
{
int a,b,s;
printf("请输入矩形的长和宽，并用空格隔开\n");
scanf("%d %d",&a,&b);
s=a*b;
printf("s=%d*%d=%d\n",a,b,s);
return 0;
}