LAB Activity 04082026

2026-04-01 20:23

Tags: #java

Author: Duke Hsu

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Key topic / concepts

• One dimensional arrays
• String class and string comparison
• charAt() , valueof(), equals, length(), equalsIgnoreCase() ,toLowerCase()
• Looping statements(for, while)
• Condition statements(if, if-else)
• Random number generation
• Classes, objects, attributes, and methods.

Ramdon

• java.util.Random;
• Random class is used to generate pseudo-random numbers in java.
• In this case, we can use rand.nextInt(wordList.length) to choose which word we get from an array .

Random word Example:

String [] wordList = {"java","object","class","array","string"}; //array size 5

Random rand = new Random();
// set secretWord = wordList[ array size],  
//rand.nextInt(5)
//rand.nextInt(5) is random 0-4 
secretWord = wordList[rand.nextInt(wordList.length)];  

Code

Main Class

package hangmangame;
import java.util.Scanner;
/**
 * @author dukehsu
 */
public class Main {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        boolean playAgain = true;

        //main WHILE Loop for ask user if they wanna play again
        while (playAgain) {
            HangmanGame game = new HangmanGame();
            System.out.println("** Welcome to Simple Hangman Game **\n");

            // sub WHILE loop for user input and letter check 
            while (true) {
                game.displayWord();
                System.out.print("Enter a letter: ");
                String userInput = input.nextLine();

                // check userInput value if not letter, reminder user try again 
                if (userInput.length() != 1 || !Character.isLetter(userInput.charAt(0))) {
                    System.out.println("Please enter a valid letter (a-z only)\n");
                    continue;
                }

                //store userInput to letter
                char letter = userInput.toLowerCase().charAt(0);
                game.guessLetter(letter);

                // win condition check - if guessedWord equals secretWord
                if (game.isWordGuessed()) {
                    System.out.println("You Win!~~");
                    System.out.println("The word was: " + game.getSecretWord()+ "\n");
                    break;
                }

                //failed condition check - if attempts <=0 ,then failed
                if (game.getAttemptsLeft() <= 0) {
                    System.out.println("Game Over!!!!");
                    System.out.println("The word was: " + game.getSecretWord()+"\n");
                    break;
                }
            }//end of sub WHILE Loop

            //ask user play again 
            System.out.print("Do you wanna play again? (y/n): ");
            String answer = input.next();

            //check user input
            if (!answer.equalsIgnoreCase("y")) {
                playAgain = false;
            }
            System.out.println("*****************\n");
        }//end of main WHILE Loop

        System.out.println("Thanks for playing! Bye");      
    }
}

HangmanGame Class

package hangmangame;
import java.util.Random;

/**
 * @author dukehsu
 */
public class HangmanGame {


    //class HanmanGame attributes
    String [] wordsList = {"java","object","function","array","string","interface","class","method"};
    String secretWord;
    char[] guessedWord;
    int attemptsLeft = 10;


    //constructor HanmanGame
    public HangmanGame() {

        //create a object
        Random rand = new Random();


        /* set secretWord = wordList[ array size],  
         * rand.nextInt(8)
         * rand.nextInt(8) is random 0-7 = index 0-7 
         */
        secretWord = wordsList[rand.nextInt(wordsList.length)];

        //set guesseWord size =  (example: java length 4)
        guessedWord = new char[secretWord.length()];

        //use for loop initialization guesseWord "_ _ _ _"
        for (int i = 0; i < guessedWord.length; i++) {
            guessedWord[i]= '_'; //hide word
        }

    }//end of constructor 

    //displayWord method
    void displayWord() {

        System.out.println("Word to guess: ");
        //use for loop display user guessedWord
        for (char c : guessedWord) {
            System.out.print(c + " ");
        }
        System.out.println();
        System.out.println("Attempts left: " + attemptsLeft);
    }


    //guessLetter method with parameter
    void guessLetter(char letter) {

        boolean found = false;

        //use for loop to check secretWord has letter 
        for (int i = 0; i < secretWord.length(); i++) {
            if (secretWord.charAt(i)== letter) {
                guessedWord[i] = letter;
                found = true;
            }
        }

        //if not fund print msg and attemptsLeft -1
        //else correct
        if (!found) {
            attemptsLeft--;
            System.out.println("Wrong guess!\n");
        } else {
            System.out.println("Correct guess!\n");
        }

    }

    //isWordGuessed method
    boolean isWordGuessed() {
        //return boolean, if guessedWord equals secretWord return TRUE, else return FALSE
        return String.valueOf(guessedWord).equals(secretWord);
    }


    //getAttemptsLeft method
    int getAttemptsLeft() {
        return attemptsLeft;
    }


    //getSecretWord method 
    String getSecretWord() {
        return secretWord;
    }
}

Output

Output 1

Output 2

**Output 3 **

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References