Codehs 4.7 11 Rock Paper Scissors

CodeHS 4.7 11 Rock Paper Scissors: A Complete Guide for Beginners

CodeHS 4.7 11 Rock Paper Scissors is one of the most widely used introductory programming assignments in the CodeHS curriculum. It helps students practice fundamental concepts such as user input, random number generation, conditional statements, and loops while building a fun, interactive game. This article walks through the entire exercise, explains the underlying logic, offers step‑by‑step implementation tips, and suggests ways to extend the project for deeper learning.

Understanding the Assignment

In CodeHS unit 4.7, lesson 11, learners are asked to create a text‑based version of the classic Rock‑Paper‑Scissors game where the computer makes a random choice and the user enters their move. The program must:

1. Prompt the user to type rock, paper, or scissors.
2. Generate a random choice for the computer.
3. Compare the two selections and announce the winner (or a tie).
4. Optionally allow the user to play again until they decide to quit.

The exercise reinforces several core programming ideas:

• Input handling – reading a string from the console.
• Randomization – using a random number generator to simulate the computer’s move. - Conditionals – evaluating win/lose/tie scenarios.
• Loops – repeating the game based on user preference. - Functions – encapsulating logic for readability and reuse.

Setting Up the Environment

Before writing code, make sure you have the CodeHS editor open for the JavaScript (or Python) track, depending on the language your class uses. The starter file typically contains a main() function and a comment indicating where to place your solution.

If you are working locally, you can use any IDE or even a simple text editor with a terminal. For JavaScript, Node.js will run the script; for Python, the standard interpreter suffices.

Step‑by‑Step Implementation

Below is a language‑agnostic outline that you can translate into either JavaScript or Python. Each step includes the key constructs you’ll need.

1. Pseudocode ```

START DISPLAY welcome message REPEAT GET userChoice from input (lowercase) IF userChoice not in ["rock","paper","scissors"] DISPLAY error message and ask again END IF UNTIL userChoice is valid

SET computerChoice to random element from ["rock","paper","scissors"]
DISPLAY both choices

IF userChoice == computerChoice
    DISPLAY "It's a tie!"
ELSE IF (userChoice == "rock" AND computerChoice == "scissors") OR
        (userChoice == "paper" AND computerChoice == "rock") OR
        (userChoice == "scissors" AND computerChoice == "paper")
    DISPLAY "You win!"
ELSE
    DISPLAY "Computer wins!"
END IF

ASK user if they want to play again
IF answer is "yes" or "y"
    LOOP back to start
ELSE
    DISPLAY farewell message
END IF

END

#### 2. Translating to JavaScript  

```javascript
function start() {
    println("Welcome to Rock Paper Scissors!");
    let playAgain = true;

    while (playAgain) {
        // ----- Get valid user input -----
        let userChoice;
        do {
            userChoice = readLine("Enter rock, paper, or scissors: ").toLowerCase();
            if (!["rock","paper","scissors"].includes(userChoice)) {
                println("Invalid choice. Please try again.");
            }
        } while (!["rock","paper","scissors"].includes(userChoice));

        // ----- Generate computer choice -----
        const choices = ["rock","paper","scissors"];
        const randomIndex = Randomizer.nextInt(0, choices.length); // 0,1,2
        const computerChoice = choices[randomIndex];

        println(`You chose: ${userChoice}`);
        println(`Computer chose: ${computerChoice}`);

        // ----- Determine the outcome -----
        if (userChoice === computerChoice) {
            println("It's a tie!");
        } else if (
            (userChoice === "rock" && computerChoice === "scissors") ||
            (userChoice === "paper" && computerChoice === "rock") ||
            (userChoice === "scissors" && computerChoice === "paper")
        ) {
            println("You win!");
        } else {
            println("Computer wins!");
        }

        // ----- Ask to play again -----
        const answer = readLine("Play again? (yes/no): ").toLowerCase();
        playAgain = (answer === "yes" || answer === "y");
    }

    println("Thanks for playing! Goodbye.");
}

3. Translating to Python

import randomdef main():
    print("Welcome to Rock Paper Scissors!")
    play_again = True    while play_again:
        # ----- Get valid user input -----
        user_choice = ""
        while user_choice not in ["rock", "paper", "scissors"]:
            user_choice = input("Enter rock, paper, or scissors: ").strip().lower()
            if user_choice not in ["rock", "paper", "scissors"]:
                print("Invalid choice. Please try again.")

        # ----- Generate computer choice -----        choices = ["rock", "paper", "scissors"]
        computer_choice = random.choice(choices)

        print(f"You chose: {user_choice}")
        print(f"Computer chose: {computer_choice}")

        # ----- Determine the outcome -----        if user_choice == computer_choice:
            print("It's a tie!")
        elif (user_choice == "rock" and computer_choice == "scissors") or \
             (user_choice == "paper" and computer_choice == "rock") or \
             (user_choice == "scissors" and computer_choice == "paper"):
            print("You win!")
        else:
            print("Computer wins!")

        # ----- Ask to play again -----
        again = input("Play again? (yes/no): ").strip().lower()
        play_again = again in ["yes", "y"]

    print("Thanks for playing! Goodbye.")

if __name__ == "__main__":
    main()

Detailed Code Explanation