poj2262 素数

/*
Time:2019.11.9
Author: Goven
type：
err:
ref:
*/
#include<iostream>
#include<cmath>
using namespace std;

bool isPrime(int x) {
    if (x == 1 || x == 0) return false;
    int l = sqrt((double)x);
    for (int i = 2; i <= l; i++) {
        if (x % i == 0) {
            return false;
        }
    }
    return true;
}

int main()
{
    int n, a, b, l, flag;
    while (cin >> n && n) {
        l = n / 2;
        flag = 1;
        for (int i = 3; i <= l; i += 2) {
            if (isPrime(i) && isPrime(n - i)) {
                printf("%d = %d + %d\n", n, i, n - i);
                flag = 0;
                break;
            }
        }
        if (flag) printf("Goldbach's conjecture is wrong.\n");
    }
    return 0;
}