Thread: Tower of Hanoi Implementation

I have to implement a program that creates the Tower of Hanoi game where there is a human play and computer plays. The human plays allows the user to solve the problems by moving the disks on pegs. The computer plays allows the computer to solve the game and prints out each move.

package prog05;
 
import java.util.Stack;
import prog02.UserInterface;
import prog02.GUI;
 
public class Tower {
  static UserInterface ui = new GUI();
 
  static public void main (String[] args) {
    int n = getInt("How many disks?");
    if (n <= 0)
      return;
    Tower tower = new Tower(n);
 
    String[] commands = { "Human plays.", "Computer plays." };
    int c = ui.getCommand(commands);
    if (c == 0)
      tower.play();
    else
      tower.solve();
  }
 
  /** Get an integer from the user using prompt as the request.
   *  Return 0 if user cancels or enters an empty string.  */
  static int getInt (String prompt) {
    while (true) {
      String number = ui.getInfo(prompt);
      if (number == null || number.length() == 0)
        return 0;
      try {
        return Integer.parseInt(number);
      } catch (Exception e) {
        ui.sendMessage(number + " is not a number.  Try again.");
      }
    }
  }
 
  int nDisks;
  StackInt<Integer>[] pegs = (StackInt<Integer>[]) new ArrayStack[3];
 
  Tower (int nDisks) {
    this.nDisks = nDisks;
    for (int i = 0; i < pegs.length; i++)
      pegs[i] = new ArrayStack<Integer>();
 
    // EXERCISE: Initialize game with pile of nDisks disks on peg 'a'
    // (pegs[0]).
  }
 
  void play () {
    while (true /* EXERCISE:  player has not won yet. */) {
      displayPegs();
      String move = getMove();
      int from = move.charAt(0) - 'a';
      int to = move.charAt(1) - 'a';
      move(from, to);
    }
 
    ui.sendMessage("You win!");
  }
 
  String stackToString (StackInt peg) {
    StackInt helper = new ArrayStack();
 
    // String to append items to.
    String s = "";
 
    // EXERCISE:  append the items in peg to s from bottom to top.
 
    return s;
  }
 
  void displayPegs () {
    String s = "";
    for (int i = 0; i < pegs.length; i++) {
      char abc = (char) ('a' + i);
      s = s + abc + stackToString(pegs[i]);
      if (i < pegs.length-1)
        s = s + "\n";
    }
    ui.sendMessage(s);
  }
 
  String getMove () {
    String[] moves = { "ab", "ac", "ba", "bc", "ca", "cb" };
    return moves[ui.getCommand(moves)];
  }
 
  void move (int from, int to) {
    // EXERCISE:  move one disk form pegs[from] to pegs[to].
    // Don't do illegal moves.  Send a warning message instead, like:
    // Cannot place 2 on top of 1.
  }
 
  // EXERCISE:  create Goal class.
 
  void solve () {
    // EXERCISE
  }        
}

A nice old game.
What questions or problems do you have?

One problem you'll have getting people to test your code is that you are using a third party package:
import prog02.UserInterface;