#include"stdio.h"
#define pi=3.1415926
void main()
{float r,h ,s1，s2 ,v;
printf("Enter  r and h:\n");
scanf("%f%f",&r,&h);
s1=pi*r*r;
printf("s1=%.4f：\n",s1);
s2=2*pi*r*h;
printf("s2=%.4f：\n",s2);
v=pi*r*r*h;
printf（"v=%.4f：\n",v）;


}

#include"stdio.h"
#define PI 3.1416
void main()
{
    float r,h,s1,s2,v;
    printf("Enter r or h:\n");
    scanf("%f%f",&r,&h);
    s1=PI*r*r;
    printf("s1=%.4f:\n",s1);
    s2=2*PI*r*h;
    printf("s2=%.4f:\n",s2);
    v=PI*r*r*h;
    printf("v=%.4f:\n",v);
}

宏定义要大写