#include<stdio.h>
#include<math.h>
void main()
{
char prime(int);/* 函数声明或定义函数原形 (Function
Prototype)*/
char ch;
int n;
printf("\nInput an integer:");
scanf("%d",&n);
ch=prime(n); // 函数调用
if(ch==‘g’)
printf("\n%d is a prime.",n);
else
printf("\n%d is NOT a prime.",n);
}