Building a Basic Program: Rock, Paper, Scissors

In this section, we’ll build a simple “Rock, Paper, Scissors” game using Recolon. This will help you understand how to implement conditional logic, use variables, and interact with users.

Step 1: Set Up the Game Structure

First, let’s define the basic structure of our program. We’ll start by writing a main function that initializes the game:

fn main() {
    log("Welcome to Rock, Paper, Scissors!");
    var player_choice = get_player_choice();
    var computer_choice = get_computer_choice();
    var result = determine_winner(player_choice, computer_choice);
    log(result);
}

main();

This code does the following:

• Welcomes the player to the game.

• Gets the player’s choice by calling the get_player_choice function.

• Determines the computer’s choice using the get_computer_choice function.

• Decides the winner by comparing the player’s choice with the computer’s choice using the determine_winner function.

• Logs the result of the game.

The Recolon interpreter reads code from top to bottom. This means that if you try to call a function before it is defined in your code, the interpreter will throw an error. Make sure all functions are defined before they are called.

Step 2: Get the Player’s Choice

Next, we’ll define the get_player_choice function, which prompts the player to enter their choice:

fn get_player_choice() {
    log("Enter your choice (rock, paper, scissors):");
    var choice = io.read_input();
    return choice;
}

This function:

• Prompts the player to enter their choice.

• Reads the input using the io.read_input() function.

• Returns the player’s choice to be used in the game.

Step 3: Generate the Computer’s Choice

Now, let’s define the get_computer_choice function, which randomly selects rock, paper, or scissors:

fn get_computer_choice() {
    var choices = ["rock", "paper", "scissors"];
    var index = math.random(0, 2);
    return choices[index];
}

This function:

• Defines an array with the possible choices: “rock”, “paper”, and “scissors”.

• Randomly selects one of the choices using the math.random() function.

• Returns the computer’s choice.

Step 4: Determine the Winner

Finally, we’ll define the determine_winner function, which compares the player’s choice with the computer’s choice to determine the winner:

fn determine_winner(player, computer) {
    var winner;

    if (player == computer) {
        winner = "It's a tie!";
    } elif (player == "rock" and computer == "scissors") {
        winner = "You win! Rock beats Scissors.";
    } elif (player == "scissors" and computer == "paper") {
        winner = "You win! Scissors beats Paper.";
    } elif (player == "paper" and computer == "rock") {
        winner = "You win! Paper beats Rock.";
    } else {
        winner = "You lose!";
    }

    return winner;
}

This function:

• Compares the player’s choice with the computer’s choice.

• Returns a message indicating whether the player won, lost, or tied.

Return statements in Recolon should always be placed at the end of functions. If a return statement is not the last line of the function, or if there are unreachable lines of code after the return statement, the function will return nil by default.

Step 5: Run the Program

With all the pieces in place, you can now run the program. Save your code in a .rcn file and execute it using the Recolon interpreter. The program will prompt you for your choice, generate the computer’s choice, and determine the winner.

Your program should look like this:

fn get_player_choice() {
    print("Enter your choice (rock, paper, scissors):");
    var choice = io.read_input();
    return choice;
}

fn get_computer_choice() {
    var choices = ["rock", "paper", "scissors"];
    var index = math.random(0, 2);
    return choices[index];
}

fn determine_winner(player, computer) {
    var winner;

    if (player == computer) {
        winner = "It's a tie!";
    } elif (player == "rock" and computer == "scissors") {
        winner = "You win! Rock beats Scissors.";
    } elif (player == "scissors" and computer == "paper") {
        winner = "You win! Scissors beats Paper.";
    } elif (player == "paper" and computer == "rock") {
        winner = "You win! Paper beats Rock.";
    } else {
        winner = "You lose!";
    }

    return winner;
}

fn main() {
    print("Welcome to Rock, Paper, Scissors!");
    var player_choice = get_player_choice();
    var computer_choice = get_computer_choice();
    var result = determine_winner(player_choice, computer_choice);
    print(result);
}

main();

Note

This basic program demonstrates core Recolon concepts such as functions, conditionals, and input/output. You can expand this game by adding more features, such as allowing the player to play multiple rounds or keeping track of the score.

By following these steps, you’ve created a simple yet complete “Rock, Paper, Scissors” game in Recolon. This exercise should give you a solid understanding of how to use Recolon’s basic features to build interactive programs.