"Золотое" сечение

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<string>
#include<alg.h>

using namespace std;
const double EPS = 1e-4;
const double DELTA = 1e-5;
const int INF = 1e8 + 13;
const double goldenRatio1 = (3 - sqrt(5)) / 2; // "Золотое" число
const double goldenRatio2 = (sqrt(5) - 1) / 2; // "Золотое" число

double func(double x)
{
    return 2. * x*x - 6 * x - 3;
}

pair<double, double> solve()
{

    double left = -1;
    double right = 3;
    double step = 0.1;
    double answer = INF;
    double answerPoint = -INF;

    double x1, x2;
    while (fabs(right - left) > EPS) {
        x1 = left + goldenRatio1*(right - left);
        x2 = left + goldenRatio2*(right - left);
        if (func(x1) >= func(x2))
            left = x1;
        else
            right = x2;
    }
    answer = func((left + right) / 2);
    answerPoint = (left + right) / 2;
    return make_pair(answer, answerPoint);
}

int main()
{
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);

    pair<double, double> ans = solve();
    cout << "min = " << ans.first << "\nwith x =  " << ans.second << endl;

}