HOJ 1459 Goldbach's Conjecture

http://acm.hit.edu.cn/hoj/problem/view?id=1459

Every even number greater than 4 can be written as the sum of two odd primenumbers.

#include<stdio.h>#include<math.h>bool pri(int n);int main(){    int n, i;    bool flag;    while (scanf("%d", &n) && n)    {        flag = 0;        for (i = 2; i <= n/2; i++)        {            if(pri(i) && pri(n-i))            {                flag = 1;                printf("%d = %d + %d\n", n, i, n-i);                break;            }        }        /*还没被证伪*/        /*        if (flag == 0)            printf("Goldbach's conjecture is wrong.\n");        */    }    return 0;}bool pri(int n){    int i;    for (i = 2; i <= sqrt(n); i++)    {        if (n % i == 0)            return 0;    }    return 1;}