10.5

题目二：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;

}