Square root approximations and loops, output not as expected

Question

Hi guys,
I'm trying to create a program that uses loops to guess the approximate value of a square root of an inputted value within an epsilon value. The program will guess with a value x, then use (x + (value/x))/2 to guess a closer value, where value = sqrt(input).
Here is my solution class:
public class RootApproximator
   public RootApproximator(double val, double eps)
          value = val;
          square = Math.sqrt(val);
          epsilon = eps;
          lower = square - epsilon;
   public double nextGuess()
          for (double i = 1; i < lower; i++)
               i = (i + (value/i)) / 2;
               guess = i;
          return guess;
   public boolean hasMoreGuesses()
          return (square - guess <= epsilon);
   private double square;
   private double value;
   private double epsilon;
   private double guess;
   private double lower;
And here is my tester:
public class RootApproximatorTester
   public static void main(String[] args)
      double a = 100;
      double epsilon = 1;
      RootApproximator approx = new RootApproximator(a, epsilon);
      System.out.println(approx.nextGuess());
      System.out.println("Expected: 1");
      System.out.println(approx.nextGuess());
      System.out.println("Expected: 50.5");
      while (approx.hasMoreGuesses())
         approx.nextGuess();
      System.out.println(Math.abs(approx.nextGuess() - 10) < epsilon);
      System.out.println("Expected: true");
}Something is wrong with my loop, because the expected values are not appearing. Here is what the output looks like:
50.5
Expected: 1
50.5
Expected: 1
... // there should be more here, it should print:
// true
// Expected: true
If anyone could please point out my errors so I can finish this program I would certainly appreciate it. Thank you all.

Answer 1

I've modified your code a bit.
class RootApproximator
     private double value;
     private double accuracy;
     private double firstGuess;
     public RootApproximator(double val)
          value = val;
          accuracy = 1;
     public double makeGuess()
          double guess = firstGuess;
          for (double i = 1; i <= accuracy; i++)
               double temp = value / guess;
               guess = (guess + temp) / 2.0;
               System.out.println("Next Guess: "+guess);
          return guess;
     public void setFirstGuess(double num)
          firstGuess = num;
     //the higher the accuracy, the closer the square root will be
     public void setAccuracy(int num)
          accuracy = num;
public class Test
     public static void main(String[] args)
          System.out.println("Number to take square root of:");
          java.util.Scanner input = new java.util.Scanner(System.in);
          double num = input.nextDouble();
          System.out.println("Number of times to iterate:");
          int acc = input.nextInt();
          System.out.println("First Guess:");
          double guess = input.nextDouble();
          RootApproximator approx = new RootApproximator(num);
          approx.setAccuracy(acc);
          approx.setFirstGuess(guess);
          double sqrt = approx.makeGuess();
          System.out.println("--------------------");
          System.out.println("Final Guess: "+sqrt);
          System.out.println("Actual Square Root: "+Math.sqrt(num));
}