Guess the number game in java

Question

package edu.blastermind.model;

import java.util.Random;

/**
 * A NumberGuessingGame represents the rules of a simple "guess the number" type game.
 * 
 * @author
 *
 */
public class GuessTheNumberGame {

    private int highest;
    private int secret;

    /**
     * Creates a new NumberGuessingGame with a secret number between 0 and highest.
     * 
     * @param highest the highest possible number for this game. Must be > 0.
     */
    public GuessTheNumberGame(int highest) {

        // TODO 1: perform a precondition check on the parameter highest
        if (highest <= 0) {
            throw new IllegalArgumentException
            ("highest number must be at least 1");
        }

        this.highest = highest;

        Random rng = new Random();

        this.secret = rng.nextInt(highest + 1);
    }

    /**
     * Checks to see if we've guessed correctly.
     * 
     * @param guess our guess (must be between 0 and getHighest())
     * @return true if the guess was correct, false otherwise
     */
    public boolean isGuessCorrect(int guess) {

        // TODO 2: perform a precondition check on the variable guess
        if (guess > this.highest || guess < 0) {
            throw new IllegalArgumentException
            ("Guess must be between 1 and 100");
        }

        return this.secret == guess;
    }

    /**
     * Checks to see if our guess is higher than the secret.
     * 
     * @param guess our guess (must be between 0 and getHighest())
     * @return true if our guess is higher than the secret, false otherwise
     */
    public boolean isGuessHigher(int guess) {

        // TODO 3: perform a precondition check on the variable guess
        if (guess > this.highest || guess < 0) {
            throw new IllegalArgumentException
            ("Guess must be between 1 and 100");
        }

        return this.secret < guess;
    }

    /**
     * Returns the highest value in the range of valid guesses.
     * 
     * @return the highest value in the range of valid guesses
     */
    public int getHighest() {
        return this.highest;
    }
}
package edu.westga.blastermind.controllers;

import java.util.Scanner;

import edu.westga.blastermind.model.GuessTheNumberGame;

public class GuessTheNumber {

    public static void main(String[] args) {

        GuessTheNumberGame game = new GuessTheNumberGame(100);
        int turns = 1;

        Scanner kb = new Scanner(System.in);

        System.out.println("Guess a nummber between 0 and 100");
        int guess = kb.nextInt();

        // TODO 4: loop as long as the guess is not correct
        while (guess <= game.getHighest() && guess >= 0) {
            guess++;
        if (guess < game.getHighest()){
            System.out.println("You guessed too high!");
        }
            else if (guess > game.getHighest()){
                System.out.println("You guessed too low!");
            }
            Scanner keyboard = new Scanner(System.in);
            String plainText = keyboard.nextLine();
        }
            turns++;

        // TODO 5: in the loop, check guesses and give hints

        System.out.printf("You guessed the number in %d turns\n", turns);
    }
}

Hello everyone I am writing a guess the number game program and my illegal argument exceptions are not working and it is saying my guesses are too high even when I enter a guess greater than 100 or less than zero. Any help is greatly appreciated. Thanks in advance.

Answer 1

This loop:

// TODO 4: loop as long as the guess is not correct
while (guess <= game.getHighest() && guess >= 0) {
    guess++;

is not doing what you state in the comment. It will make your guess variable reach the highest value always. No check against the secret number is done.

Update 1

Replace your main method with this:

public static void main(String[] args) {

    GuessTheNumberGame game = new GuessTheNumberGame(100);
    int turns = 1;
    int guess = -1;

    do {
        Scanner kb = new Scanner(System.in);

        System.out.println("Guess a nummber between 0 and 100");
        guess = kb.nextInt();

        if (game.isGuessHigher(guess)){
            System.out.println("You guessed too high!");
            turns++;
        } else if (!game.isGuessCorrect(guess)){
            System.out.println("You guessed too low!");
            turns++;
        }
    } while (!game.isGuessCorrect(guess));
    System.out.printf("You guessed the number in %d turns\n", turns);
}

I've not executed it, so it may contain some minor problems.