TheAlgorithms-C-Plus-Plus/Computer Oriented Statistical Methods/Bisection_method.CPP

#include<iostream.h>
#include<conio.h>
#include<math.h>

float eq(float i)
{
	return (pow(i,3)-(4*i)-9);             // original equation
}

void main()
{
	float a,b,x,z;
	clrscr();
	for(int i=0;i<100;i++)
	{
		z=eq(i);
		if(z>=0)
		{
			b=i;
			a=--i;
			goto START;
		}
	}

	START:

	cout<<"\nFirst initial: "<<a;
	cout<<"\nSecond initial: "<<b;
	for(i=0;i<100;i++)
	{
		x=(a+b)/2;
		z=eq(x);
		cout<<"\n\nz: "<<z<<"\t["<<a<<" , "<<b<<" | Bisect: "<<x<<"]";

		if(z < 0)
		{
			a=x;
		}
		else
		{
			b=x;
		}

		if(z > 0 && z<0.0009)			// stoping criteria
		{
			goto END;
		}
	}

	END:
	cout<<"\n\nRoot: "<<x;
	getch();
}