/*==================================================================
Written by:		Roberto Mojica
Last revision:	10 February 2007
--------------------------------------------------------------------
Programs that finds a single root of a function f(x) on an interval
[a,b] using the bisectional method or the false position method.
==================================================================*/
#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;

//configuration
#define PI 3.1415926535897932385
#define MAX_NUM_OF_ITERATIONS 10000
#define LEFT_END_POINT 1
#define RIGHT_END_POINT 4
#define EPS 1.0e-6

#define _Fx(X) exp(X)*log(X)-cos(X*X)
//#define _Fx(X) log((X*X)+2)*cos(X)+sin(X)
//#define _Fx(X) exp(X)-sin((PI*X)/3)
//#define _Fx(X) X*X-6*X+9

double f(double x) {return (_Fx(x));}
int main() {
	cout.setf(ios::fixed | ios::showpoint);
    cout.precision(10);

	double xO,xL=LEFT_END_POINT,xR=RIGHT_END_POINT;
    int iterations=0;

	if(f(xL)*f(xR) <= 0) {
		while (fabs(xR-xL) >= EPS && (iterations++) <= MAX_NUM_OF_ITERATIONS) {
			xO=(xL+xR)/2.0; //bisectional
			//xO=xR-f(xR)*(xR-xL)/(f(xR)-f(xL)); //false position
			if((f(xL)*f(xO)) <= 0) xR=xO;
			else xL=xO;
		}
		cout << "xO = " << xO << endl;
	}
	cout << "iterations = " << iterations << endl;
    system("pause");
	return iterations;
}