编程求哥德巴赫猜想

#include <iostream>
using namespace std;

bool isPrime(int x)
{
    if(x < 2) return false;
    for(int i = 2; i*i <= x; i++)
    {
        if(x % i == 0)
            return false;
    }
    return true;
}

int main()
{
    int n;
    cin >> n;
    
    for(int num = 4; num <= n; num += 2)
    {
        bool ok = false;
        for(int a = 2; a <= num/2; a++)
        {
            int b = num - a;
            if(isPrime(a) && isPrime(b))
            {
                cout << num << "=" << a << "+" << b << " ";
                ok = true;
                break; //找到第一组就停止
            }
        }
        if(!ok)
        {
            cout << "验证失败！";
        }
    }
    return 0;
}