Дихотомии

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

using namespace std;
const double EPS = 1e-3;
const double DELTA = 1e-5;
const int INF = 1e8 + 13;



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;
	while (right - left > EPS)
	{
		double mid = (left + right) / 2;
		double F1 = func(mid - DELTA);
		double F2 = func(mid + DELTA);
		if (F1 > F2)
			left = mid;
		else
			if (F2 > F1)
				right = mid;
		if (F1 == F2)
			return { F1, mid };
	}
	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;

}