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

double my_root(double x)
{
  double guess;
  const double epsilon = 0.00001;

  guess = 1;
  while((guess * guess < x - epsilon) || (guess * guess > x + epsilon)) {
    guess = (x / guess + guess) / 2;
  }

  return guess;
}

int main()
{
  double v = 6;

  printf("sqrt(%f) = %f | %f\n", v, sqrt(v), my_root(v));

  return 0;
}