C Program to Implement NEWTON RAPHSON METHOD

/*
  Program to Implement NEWTON RAPHSON METHOD to solve eqn.
  EQN -> 3*x - cos(x) - 1 = 0.
*/

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

// Formulae Declaration
#define f(x)   3*x - cos(x) - 1
#define df(x)  3+sin(x)
int n;

void NEW_RAP();

void main()
{
clrscr();
printf("\n Solution by NEWTON RAPHSON METHOD ");
printf("\n\n Equation is -> 3*x - cos(x) - 1 = 0\n");
printf("\n Enter the no. of iterations ");
scanf("%d",&n);
NEW_RAP();
getch();
}

void NEW_RAP()
 {
 float x1,x0;
 float f1,f0;
 float df0;
 int i=1,itr;
 float EPS,error;

 /* finding an approximate Root of a given equation, having +ve value*/
 for(x1=0.0;;x1+=0.01)
    {
    f1=f(x1);
    if(f1>0)
      break;
    }
 itr=n;
 x0=x1-0.01;
 f0=f(x0);
 printf("\n Enter the Maximum possible error: ");
 scanf("%f",&EPS);
 if(fabs(f0)>f1)
   printf("\n\t\t The root is near to %.4f\n\n\n",x1);
 if(f1>fabs(x0))
   printf("\n\t\t The root is near to %.4f\n\n\n",x0);
 x0=(x0+x1)/2;
 for(;i<=itr;i++)
    {
    f0=f(x0);
    df0=df(x0);
    x1=x0-(f0/df0);
    printf("\n\t\t The %d approximation to the root is : %f",i,x1);
    error=fabs(x1-x0);
    if(error<EPS)
      break;
    x0=x1;
    }
 if(error>EPS)
   {
   printf("\n\n\t NOTE :-");
   printf(" The No. of Iterartions are not sufficient. ");
   }
 printf("\n\n\n\t\t----------------------------------------------------");
 printf("\n\t\t ROOT  = %.4f ",x1);
 printf("\n\t\t----------------------------------------------------");
}