圆的面积

#include <stdio.h>
#define PI 3.14
double calculatingarea(int radius);
int main()
{
    int cRadius=0;
    double area=0.0;
    printf("请输入圆的半径:\n");
    scanf("%d",&cRadius);
    area =calculating area(cRadius);
    printf("圆的面积是：%f\n",area);
    return 0;
}
    double calculatingarea(int radius)
{
        double result=PI*radius*radius;
        return result;
}