// Secant Method

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

// Set tolerance
#define ESP 0.0001
// Function definition; adjust per your requirement
#define F(x) (x)*(x) - 4*(x) - 10


// Start of main program
main()
{
  float x1, x2, x3, f1, f2, t;

  printf("\nEnter the value of x1: ");
  scanf("%f",&x1);
  printf("\nEnter the value of x2: ");
  scanf("%f",&x2);
  printf("\n----------------------------------------------\n");
  printf("\n    x1\t  x2\t  x3\t     f(x1)\t f(x2)");
  printf("\n----------------------------------------------\n");

  do
  {
    f1 = F(x1);
    f2 = F(x2);
    x3 = x2 - ((f2*(x2-x1))/(f2-f1));
    
    printf("\n%f   %f   %f   %f   %f", x1, x2, x3, f1, f2);
    x1 = x2;
    x2 = x3;
    if (f2 < 0)
	t=fabs(f2);
    else
	t = f2;
  } while(t > ESP);

printf("\n------------------------------------------------\n");
printf("\n\nApp.root = %f",x3);

getchar();
}