Xcode的一个警告不知道该怎么解决

#include<iostream>
#include <array>
#include <vector>
#include <cmath>
using namespace std;

int main()
{
    vector<int> x = {1, 2, 3, 4};
    vector<int> y = {6, 5, 7, 10};
    
    int n = x.size();
    double a = 0, b = 0, lr = 0.001;
    while(true)
    {
        double g_a = 0, g_b = 0;
        for(int i = 0; i < n; i++)
        {
            g_a += 2 * x[i] * (a * x[i] + b - y[i]);
            g_b += 2 * (a * x[i] + b - y[i]);
        }
        g_a /= n;
        g_b /= n;
        a = a - lr * g_a;
        b = b - lr * g_b;
        double loss = 0;
        for(int i = 0; i < n; i++)
        {
            loss += pow((a * x[i] + b - y[i]), 2);
        }
        if(loss < 4.2)
            break;
    }
    cout << a << endl;
    cout << b << endl;
}

网上的方法无效
什么把-w修改为-wno