# include <cstdlib>
# include <iostream>
# include <cmath>

using namespace std;

int main ( )
//
//  SQROOT_DO_WHILE estimates a square root using a DO...WHILE statement.
//
{
  double error, h, w, x;

  cout << "Enter number whose square root is desired: ";
  cin >> x;

  h = x;
  w = x / h;
  error = x - h * h;

  while ( 0.00001 < fabs ( error ) )
  {
    h = ( h + w ) / 2.0;
    w = x / h;
    error = x - h * h;
  }
  
  cout << "\n";
  cout << "Number X = " << x << "\n";
  cout << "Estimated square root = " << h << "\n";
  cout << "Error | x - h * h | = " << error << "\n";

  return 0;
}