Towers Of Hanoi Java

Question

This is a homework that I was working on. I have created 2 classes to play Towers of Hanoi. The first one is the basically a runner to run the actual game class.

import java.util.Scanner;

class TowersRunner {

    public static void main(String[] args) {
        TowersOfHanoi towers = new TowersOfHanoi();
        towers.TowersOfHanoi()
    }
}

public class TowersOfHanoi {
    public static void main(String[] args) {


        System.out.println("Please enter the starting " + "number of discs to move:");
        Scanner scanner = new Scanner(System.in);
        int num_of_discs = scanner.nextInt();

        solve(num_of_discs, 'A', 'B', 'C');
    }

    public static void solve(int first_disc, char aTower, char bTower, char cTower) {
        if (first_disc == 1) {
            System.out.println("Disk 1 on tower " + aTower + " moving to tower " + cTower);
        } else {
            solve(first_disc - 1, aTower, cTower, bTower);
            System.out.println("Disk " + first_disc + " on tower " + aTower + " moving to tower " + cTower);
            solve(first_disc - 1, bTower, aTower, cTower);
        }
    }
}

What I need help with is to make the TowersOfHanoi class to run from my TowersRunner class. I also need to implement a counter display how many times it took for the game to run until the game is finished in my TowersOfHanoi class. Basically I need line that is System.out.println("It took" + counter + "turns to finish.");

I don't know how to implement the counter correctly. Also, can't make the runner class to run the TowersOfHanoi. The TowersOfHanoi class runs fine by itself but the requirment for the homework is we need at least 2 classes min.

Help would be much appreciated!!! Please I am a novice in Java and programming in general please don't go too advanced on me. :D

Answer 1

You don't need the main-Function in the TowersOfHanoi class. Instead, replace your TowersRunner main(String args[]) method with

public static void main(String[] args) {    
    System.out.println("Please enter the starting " + "number of discs to move:");
    Scanner scanner = new Scanner(System.in);
    int num_of_discs = scanner.nextInt();
    TowersOfHanoi.solve(num_of_discs, 'A', 'B', 'C');
}

Answer 2

You can just pass the counter in the function and have it be incremented. For example:

public static void solve(int first_disc, char aTower, char bTower, char cTower, int counter) {
    System.out.println("Currently on turn #" + counter);

    if (first_disc == 1) {
        System.out.println("Disk 1 on tower " + aTower + " moving to tower " + cTower);
    } else {
        solve(first_disc - 1, aTower, cTower, bTower, counter + 1);
        System.out.println("Disk " + first_disc + " on tower " + aTower + " moving to tower " + cTower);
        solve(first_disc - 1, bTower, aTower, cTower, counter + 1);
    }
}

In the first call of solve, you would pass in 1. As you can see, each time solve is called recursively, the counter is incremented.

I'll leave you to adapt this to return the final value of counter :) If you just need the final value, you don't need to add a parameter at all. Just make the function return int instead of void then try and figure out how you would make it return the value you want.