Program to find the roots of a polynomial equation using bisection method

#include<stdio.h>

#include<conio.h>

#include<math.h>

#define f(x) x*x*x-x-1

int main()

{

float x0,x1,e,y0,y1,x2,y2;

int i=0;

printf("enter the initial guesses\n");

scanf("%f%f",&x0,&x1);

printf("enter the prescribed precision value\n");

scanf("%f",&e);

y0=f(x0);

y1=f(x1);

if(y0*y1>0)

{

  printf("initial guesses are not suitable\n");

  return(0);

}

//printline();

printf("iter\tX0\tF(X0)\tX1\tF(X1)\tX2\tF(X2)\n");

//printline();

while (fabs((x1-x0)/x1)>=e)

{

  x2=(x0+x1)/2;

  y2=f(x2);

  i=i+1;

  printf("  %d\t%.2f\t%.2f\t%.2f\t%.2f\t%.2f\t%.2f\n",i,x0,y0,x1,y1,x2,y2);

  if(y0*y2>0)

  {

    x0=x2;

}

  else

  {

    x1=x2;

}

}

printf("converges to the root\n");

printf("number of iteration is %d\n",i);

printf("root is %.2f",x2);

getch();

}