输出基本信息

#include<stdio.h>
int main()
{
   printf("hello qingdao!);
}

求圆表面积

#include <stdio.h>  
#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 calculateArea(int radius)    
{ 
    double result = PI*radius*radius;  
    return result;   
 }