【正经题解】Gold King假想

#include<iostream>
using namespace std;

// 判断一个数是否为素数
bool isPrime(int n) {
    if (n < 2) 
        return false;
    for (int i = 2; i <= n / i; ++i)
        if (n % i == 0) 
            return false;
    return true;
}

// 验证哥德巴赫猜想
void goldbach(int n) {
    if (n < 6 || n % 2 == 1) 
        cout << "Goldbach's conjecture is wrong." << endl;
    else {
        for (int i = 3; i <= n / 2; i += 2) {
            if (isPrime(i) && isPrime(n - i)) {
                cout << n << " = " << i << " + " << n - i << endl;
                break;
            }
        }
    }
}

int main() {
    int n;
    while (1) {
        cin >> n;
        if (n == 0) 
            break;
        goldbach(n);
    }
    return 0;
}