# include <stdio.h>int main(){    int a;    float b,c,e;    printf("请输入圆的半径：");    scanf("%d",&a);    e=3.1415926;    b=(a*2)*e;    c=(4*e*a*a*a)/3.0;    printf("圆的周长是：%.2f，圆的体积为：%.2f",b,c);    return 0;}