Complete Square Root Program

In the completed program, the roles of "oldGuess" and of "newGuess" can both be played by the variable guess.

class  squareRoot
{

  public static void main( String[] args ) 
  {
    final double smallValue = 1.0E-14 ;
    double N     = 3.00 ;
    double guess = 1.00 ;

    while ( Math.abs( N/(guess*guess) - 1.0 ) > smallValue )
    {
       // calculate a new value for the guess
       guess =  N/(2*guess) + guess/2 ;

    }

    System.out.println("The square root of " + N + " is " + guess ) ;
  }

}

Here is the output of the program:

C:\users\default\JavaLessons/chap16>java squareRoot
Symantec Java! JustInTime Compiler Version 210.063 for JDK 1.1.3
Copyright (C) 1996-97 Symantec Corporation

The square root of 3.0 is 1.7320508075688772

The last several digits of this output are probably in error since the program only computes 14 decimal places of accuracy.