Program to find the roots of a polynomial equation using newton raphson method

#include<stdio.h>

#include<conio.h>

#include<math.h>

#define f(x) x*x*x-5*x+3

#define df(x) 3*x*x-5

//int printline()

//{

//int i;

//for(i=1;i<=60;i++)

//printf("-");

//printf("\n");

//}

int main()

{

float x0,x1,y0,dy0,e,delta;

int i,n;

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

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

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

scanf("%f",&e);

printf("enter the maximum number of iteration\n");

scanf("%d",&n);

printf("enter the minimum allowed value of slope\n");

scanf("%f",&delta);

//printline();

printf("iter\tX0\tF(X0)\tF'(x0)\tX1\n");

//printline();

for(i=1;i<=n;i++)

{

  y0 = f(x0);

  dy0= df(x0);

  if ((fabs(dy0)) < delta)

  {

    printf("slope is too small\n");

    return(0);

  }

  x1=x0-(y0/dy0);

  printf("  %d\t%.2f\t%.2f\t%.2f\t%.2f\n",i,x0,y0,dy0,x1);

  if ((fabs(x1-x0)/x1)<=e)

  {

    //printline();

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

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

    printf("root is %.2f\n",x1);

    getch();

    return(0);

  }

  x0=x1;

}

//printline();

printf("does not converges to the root in %d iteration",n);

getch();

}