作业二：圆的面积
```
#include
#define PI 3.14
double calculateArea (int radius);
int main ()
{
int cRadius =0;
double Area =0.0;
printf("请输入圆的半径:\n");
scanf("%d",&cRadius);
Area=calculateArea(cRadius);
printf("圆的面积是:%f\n",Area);
return 0;
}
double calculateArea (int radius)
{
double result = PI*radius*radius;
return result;
}
```
