题解 | #KiKi设计类继承#

#include <stdio.h>
int ju(int c,int k){return c*k;}
float yuan(int a){return a*a*3.14;}
int zheng(int a){return a*a;}
int main()
{
    int c,k;
    scanf("%d %d",&c,&k);
    int y;
    scanf("%d",&y);
    int z;
    scanf("%d",&z);
    printf("%d\n",ju(c,k));
    float x=yuan(y);
    int xx=100*(x-(int)x);
    if(xx==0)printf("%d\n",(int)x);
    else if(xx%10==0)printf("%.1f\n",x);
    else printf("%.2f\n",x);
    printf("%d\n",zheng(z));
}