一道很简单的题目，上代码：

#include <iostream>
#include <algorithm>
using namespace std;
bool is_prime(int x) {
    if (x < 2 || (x > 2 && x % 2 == 0)) return false;
    for (int i = 3; i * i <= x; ++i)
        if (x % i == 0) return false;
    return true;
}
int main() {
    int n;
    while (~scanf("%d", &n)) {
        if (n == 0) break;
        bool flag = false;
        for (int i = 3; i <= n / 2; i += 2)
            if (is_prime(i) && is_prime(n - i)) {
                printf("%d = %d + %d\n", n, min(i, n - i), max(i, n - i));
                flag = true;
                break;
            }
        if (!flag) puts("Goldbach's conjecture is wrong.");
    }
    return 0;
}

基础知识：质数（素数）的判断