#include "stdafx.h"
#include <iostream>
#include <cmath>
using namespace std;
double f(double x)
{
return x*x - 3;
}
double derivative(double x)
{
return 2*x;
}
double sign(double f)
{
return f >= 0;
}

double newton(double a, double b, double eps)
{
double x = (a + b) / 2;
double x1 = 0;
for(; abs(x-x1) > eps;)
{
x1 = x;
if (derivative(x) == 0 && f(x) != 0)
{
cout << "Newton Method can not be used!";
return 0;
}
if (derivative(x) == 0 && f(x) == 0)
{
cout << "Newton Method = 0";
return 0;
}
x = x - f(x) / derivative(x);
}
return x;
}

void iter(double a, double b, double eps)
{
double x = (a + b) / 2;
for (int i = 0;; ++i)
{
double x0 = x + f(x);
if (x == x0)
{
cout << "Iteration method  = " << x << endl;
return;
}
if (i == 10) {
if (abs(x0-x) < eps)
{
cout << "Iteration method priblizitelno = " << (x0 + x) / 2 << endl;
return;
}
else
{
cout << "Iteration method ne imeet resheniya" << endl;
return;
}
}
x = x0;
}
}

double bisec(double a, double b, double eps)
{
double res = (a + b)/2;
for (; abs(b-a) > eps; )
{
if (sign(f(a)) == sign(f(res)))
{
a = res;
}
else
{
b = res;
}
if (f(res) == 0)
{
return res;
}
res = (a + b) / 2;
}
return res;
}

int main(int argc, char* argv[])
{
double a, b, eps;
cout << "Enter a, b and eps" << endl;
cin >> a >> b >> eps;
cout << "Bisection method result: " << bisec(a, b, eps) << endl;
cout << "Iterazii method result: " << iter(a, b, eps) << endl;
cout << "Newtona method result: " << newton(a, b, eps) << endl;
}
return 0;
}