Activity 2.7 Rock, Paper, Scissors

Introduction

In this activity, you will use loops and selection statements to create the classic game of Rock, Paper, Scissors.

Objectives

Implementing game logic if statements and loops

Activity Tasks

Create a new project named 2-7-Rock-Paper-Scissors.
Complete each task individually.

Task 1: Initialize Game Data

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import java.util.Scanner;
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public class Program {
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    public static void main(String[] args) {
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        Scanner input = new Scanner(System.in);
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        int wins = 0;
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        int losses = 0;
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        int round = 1;
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        boolean playing = true;
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        String player;
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        String computer;
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        /*
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        Rules:
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        Rock smashes Scissors
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        Paper covers Rock
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        Scissors cuts Paper
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        */
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        System.out.println("--- Rock, Paper, Scissors ---");
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    }
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}

Task 2: Begin Core Game Loop

Display the round number and Wins/Losses.
User inputs rock, paper, or scissors.
Computer generates a random hand.

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import java.util.Scanner;
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public class Program {
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    public static void main(String[] args) {
16 collapsed lines
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        Scanner input = new Scanner(System.in);
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        int wins = 0;
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        int losses = 0;
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        int round = 1;
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        boolean playing = true;
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        String player;
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        String computer;
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        /*
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        Rules:
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        Rock smashes Scissors
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        Paper covers Rock
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        Scissors cuts Paper
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        */
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        System.out.println("--- Rock, Paper, Scissors ---");
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        while (playing) {
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            System.out.println("Round " + round);
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            System.out.println("W: " + wins + " - L: " + losses + "\n");
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            System.out.print("(rock, paper, scissors): ");
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            player = input.nextLine().toLowerCase();
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            // Pick computer hand
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            int random = (int)(Math.random() * 3); // 0 to 2
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            if (random == 0) {
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                computer = "rock";
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            }
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            else if (random == 1) {
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                computer = "paper";
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            }
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            else {
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                computer = "scissors";
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            }
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            System.out.println("Computer chooses " + computer + "!");
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        }
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    }
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}
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//

Task 3: Implement Win/Loss Conditions

If player and computer pick the same hand: tie.
There are three possible win conditions.
If the player neither ties nor wins, they lose.

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import java.util.Scanner;
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public class Program {
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    public static void main(String[] args) {
17 collapsed lines
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        Scanner input = new Scanner(System.in);
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        int wins = 0;
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        int losses = 0;
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        int round = 1;
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        boolean playing = true;
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        String player;
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        String computer;
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        /*
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        Rules:
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        Rock smashes Scissors
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        Paper covers Rock
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        Scissors cuts Paper
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        */
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        System.out.println("--- Rock, Paper, Scissors ---");
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        while (playing) {
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            System.out.println("Round " + round);
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            System.out.println("W: " + wins + " - L: " + losses + "\n");
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            System.out.print("(rock, paper, scissors): ");
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            player = input.nextLine().toLowerCase();
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            // Pick computer hand
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            int random = (int)(Math.random() * 3); // 0 to 2
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            if (random == 0) {
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                computer = "rock";
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            }
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            else if (random == 1) {
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                computer = "paper";
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            }
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            else {
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                computer = "scissors";
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            }
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            System.out.println("Computer chooses " + computer + "!");
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            // Regarding the win condition:
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            // It's okay to break a condition over multiple lines if it get too long.
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            if (player.equals(computer)) {
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                System.out.println("-TIE-");
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            }
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            else if (
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                (player.equals("rock") && computer.equals("scissors")) ||
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                (player.equals("paper") && computer.equals("rock")) ||
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                (player.equals("scissors") && computer.equals("paper"))
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            ) {
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                System.out.println("-YOU WIN-");
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                wins++;
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            }
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            else {
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                System.out.println("-YOU LOSE-");
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                losses++;
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            }
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            round++;
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            System.out.print("Play again? (yes/no) ");
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            String choice = input.nextLine();
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            if (choice.equals("no")) {
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                playing = false;
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            }
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        }
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    }
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}
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//

Task 4: Show Final Score

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import java.util.Scanner;
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public class Program {
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    public static void main(String[] args) {
16 collapsed lines
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        Scanner input = new Scanner(System.in);
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        int wins = 0;
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        int losses = 0;
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        int round = 1;
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        boolean playing = true;
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        String player;
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        String computer;
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        /*
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        Rules:
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        Rock smashes Scissors
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        Paper covers Rock
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        Scissors cuts Paper
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        */
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        System.out.println("--- Rock, Paper, Scissors ---");
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        while (playing) {
47 collapsed lines
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            System.out.println("Round " + round);
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            System.out.println("W: " + wins + " - L: " + losses + "\n");
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            System.out.print("(rock, paper, scissors): ");
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            player = input.nextLine().toLowerCase();
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            // Pick computer hand
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            int random = (int)(Math.random() * 3); // 0 to 2
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            if (random == 0) {
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                computer = "rock";
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            }
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            else if (random == 1) {
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                computer = "paper";
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            }
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            else {
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                computer = "scissors";
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            }
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            System.out.println("Computer chooses " + computer + "!");
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            // Regarding the win condition:
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            // It's okay to break a condition over multiple lines if it get too long.
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            if (player.equals(computer)) {
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                System.out.println("-TIE-");
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            }
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            else if (
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                (player.equals("rock") && computer.equals("scissors")) ||
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                (player.equals("paper") && computer.equals("rock")) ||
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                (player.equals("scissors") && computer.equals("paper"))
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            ) {
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                System.out.println("-YOU WIN-");
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                wins++;
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            }
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            else {
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                System.out.println("-YOU LOSE-");
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                losses++;
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            }
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            round++;
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            System.out.print("Play again? (yes/no) ");
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            String choice = input.nextLine();
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            if (choice.equals("no")) {
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                playing = false;
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            }
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        }
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        System.out.println("\n--- Final Score ---");
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        System.out.println("Wins: " + wins + " - Losses: " + losses);
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        System.out.println("Thanks for playing!");
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    }
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}
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//

Sample Output

Your program output should something similar to the sample output below.

--- Rock, Paper, Scissors ---
Round 1
W: 0 - L: 0

(rock, paper, scissors): rock
Computer chooses scissors!
-YOU WIN-
Play again? (yes/no) y
Round 2
W: 1 - L: 0

(rock, paper, scissors): paper
Computer chooses paper!
-TIE-
Play again? (yes/no) y
Round 3
W: 1 - L: 0

(rock, paper, scissors): scissors
Computer chooses rock!
-YOU LOSE-
Play again? (yes/no) n

--- Final Score ---
Wins: 1 - Losses: 1
Thanks for playing!

Reflection Questions

You may write your reflection answers as comments at the bottom of your code.

If you wanted to play best-of-5 instead of a continuous game, how would you change the while loop condition?

Submission

Submit your activity and reflection answers to the appropriate dropbox.