C Program to Implement ITERATION METHOD

/*
  Program to Implement ITERATION METHOD.
  EQN -> x*x*x - 2*x + 1 = 0.
*/

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

#define EPS 0.00005
#define F(x) (x*x*x + 1)/2
#define f(x)  x*x*x - 2*x + 1

int n;

void iter();

void main()
{
clrscr();
printf("\n Solution by ITERATION METHOD ");
printf("\n\n Equation is -> x*x*x - 2*x + 1 = 0\n");
printf("\n Enter the no. of iterations ");
scanf("%d",&n);
iter();
getch();
}

void iter()
 {
 int i=0;
 float x1,x2,x0;
 float f1,f2,f0,error;
 for(x1=1; ;x1++)
    {
    f1=f(x1);
    if(f1>0)
      break;
    }
 for(x0=x1-1; ;x0--)
    {
    f0=f(x0);
    if(f0<0)
      break;
    }
 x2=(x0+x1)/2;
 printf("\n\n\t\t The 1 approximatrion to the root is : %f",x2);
 for(;i<n-1;i++)
    {
    f2=F(x2);
    printf("\n\n\t\t The %d approximatrion to the root is : %f",i+2,f2);
    x2=F(x2);
    error=fabs(f2-f1);
    if(error<EPS)
       break;
    f1=f2;
    }
 if(error>EPS)
   printf("\n\n\t NOTE :- The no. of iterations are not sufficient.");
 printf("\n\n\n\t\t -----------------------------------------------");
 printf("\n\t\t ROOT  = %.4f (Correct to 4 Decimal places)",f2);
 printf("\n\t\t -----------------------------------------------");
}