题目:​​http://acm.hdu.edu.cn/showproblem.php?pid=2002​

#include <stdio.h>
#define PI 3.1415927
int main()
{
double r;
while(scanf("%lf",&r)!=EOF)
printf("%.3lf\n",4/3.0*PI*r*r*r);
return 0;
}