10.5

题目一:简单输出

#include<stdio.h>
int main( )
{
   printf("hello Hanghang");
   return 0;
}

题目二:计算圆的面积

#include<stdio.h>
#define PI 3.14
double calculateSquare(int radius);
int main( )
{
   int cRadius=0;
   double square=0.0;
   print("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=PI*radius*radius;
   return result;
}