Question

I’ve written a Binary Tree program that asks the user questions to learn about certain animals.

My problem is that when my program asks the user “Continue?” I want the loop to begin again but I am not sure how to accomplish this. It occurs twice in my while loop and once in my learn method at the bottom. Does anybody have any ideas about how I can accomplish this?

import java.util.*;

public class AnimalGuessing  {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);  


    TreeNode<String> leftTree = new TreeNode<String> ("cat");
    TreeNode<String> rightTree = new TreeNode<String> ("snake");
    TreeNode<String> gameTree = new TreeNode<String>( "Does it have legs?",leftTree,rightTree); 

    TreeNode<String>curr = gameTree;
    String response;
    System.out.println("");
    System.out.println("");
    System.out.println("Think of an animal and I will guess it.");

    while(!(curr.getLeft() == null && curr.getRight()==null)){
        System.out.print(curr.getItem());
        response = scan.nextLine();
        if (response.equals("YES")){
            curr = curr.getLeft();

            System.out.print("Is it a " + curr.getItem() + "?");
            response = scan.nextLine();
            if (response.equals("YES")){
                System.out.println("I win! Continue?");
                response = scan.nextLine();
                if (response.equals("YES")){
                    //-----------------------
                    // I want it to restart
                    // the while loop here!
                    //-----------------------
                }
                else{
                    System.out.println("Good-bye.");
                }
            }
            else{
                learn(curr);
            }

        }//end if
        if (response.equals("NO")){
            curr = curr.getRight();
            System.out.println("is it a " + curr.getItem() + "?");
            response = scan.nextLine();
            if (response.equals("YES")){
                System.out.println("I win! Continue?");
                response = scan.nextLine();
                if (response.equals("YES")){
                    //-----------------------
                    // I want it to restart
                    // the while loop here!
                    //-----------------------
                }
                else{
                    System.out.println("Good-bye.");
                }
            }
            else{
                learn(curr);
            }
        }
    }//end while

}//end main

    //----------------------------------
    //
    // Use to add new animals/questions
    // to the tree.
    //
    //----------------------------------
    public static void learn(TreeNode<String> current){
        Scanner scan = new Scanner(System.in);
          String guessAnimal;   // animal just guessed guessed
          String correctAnimal; // animal user was thinking of
          String newQuestion;   // A question to distinguish the two
          String response;

          // Set Strings for the guessed animal and correct animal and a new question.
          guessAnimal = current.getItem();
          System.out.print("I give up. What is it? ");
          correctAnimal = scan.nextLine( );
          System.out.println("Please type a question whose answer is yes for a " +correctAnimal);
          System.out.print("and no for a " + guessAnimal + ".");
          newQuestion = scan.nextLine( );


          // Put the new question in the current node, and add two new children.
          current.setItem(newQuestion);
                current.setLeft(new TreeNode<String>(correctAnimal, null, null));
                current.setRight(new TreeNode<String>(guessAnimal, null, null));

          System.out.println("Continue?");
          response = scan.nextLine();
              if (response.equals("YES")){
                //--------------
                //I want it to
                //restart here!
                //--------------

              }
              else{
                  System.out.println("Good-bye.");
              }
       }//end learn 







}//end AnimalGuessing

Answer 1

if its homework I won’t write the answer but explain

What you want to do it to add a loop around that code

then you need to add a condition to exit the loop (like a boolean loopAgain)

this way when you want to restart your adventure, you set the boolean to true

if the user has finished you set the boolean to false.