include<stdio.h>

define PI 3.14

double calculateSquare(int radius);
int main()
{
int cRadius=0;
double square=0.0;
printf("请输入圆的半径：\n");
scanf("%d",&cRadius);
square=calculateSquare(cRadius);
printf("圆的面积是：%f\n",square);
return 0;
}
double calculateSquare(int radius)
{
double result=PIradiusradius;
return result;
}