This course builds a classic Rock Paper Scissors game in C++ using a modular programming method for a beginner-level coder

cpp.tar.gz

After learning the basics of C++, it’s a great idea to complete at least one hands-on project where you can build something from scratch using C++. This course offers the opportunity to build a basic but classic Rock Paper Scissors game, command-line style.

You’ll begin the course by looking at the end product and then building the game step-by-step, adding one tiny feature in each lesson. This way, you’ll add one or two helper functions to the codebase and then test them individually in the main controller function. Because of this modular approach, you’ll finish coding the game efficiently and professionally.

By the end of the course, you’ll have one complete hands-on project in C++ added to your profile. That’s a great start!

Mini Course: Build Rock Paper Scissors with C++

# What we have

We have catered to all the components of the game. We've created all the game’s functionalities, but have we sorted our game yet? This is our inventory of already created functions:

```C++
// Function to display game introduction and rules
void displayIntroductionAndRules() {
    cout << "Welcome to Rock-Paper-Scissors game!\n" << endl;
    cout << "The rules of the game are simple:" << endl;
    cout << "1. Rock beats scissors" << endl;
    cout << "2. Scissors beats paper" << endl;
    cout << "3. Paper beats rock" << endl;
}

// Function to get number of rounds
int getRound() {
    int rounds;
    cout << "How many rounds would you like to play? ";
    cin >> rounds;
    return rounds;
}

// Function to get player's choice
string getPlayerChoice() {
    string choice;
    cout << "Choose rock, paper, or scissors: ";
    cin >> choice;
    return choice;
}

// Function to generate computer's choice
string generateComputerChoice() {
    srand(time(NULL));
    int rand_num = rand() % 3;
    if (rand_num == 0) {
        return "rock";
    } else if (rand_num == 1) {
        return "paper";
    } else {
        return "scissors";
    }
}

// Function to determine the winner of the round and update scores
void determineWinner(string player_choice, string computer_choice) {
    if (player_choice == computer_choice) {
        cout << "It's a tie!" << endl;
    } else if ((player_choice == "rock" && computer_choice == "scissors") ||
               (player_choice == "scissors" && computer_choice == "paper") ||
               (player_choice == "paper" && computer_choice == "rock")) {
        cout << "You win!" << endl;
        player_score++;
    } else {
        cout << "The computer wins!" << endl;
        computer_score++;
    }
}

// End Game
void endGame(){
    cout << "The final score is: " << "You" << " " << player_score << " - Computer " << computer_score << endl;
    if (player_score > computer_score) {
        cout << "Congratulations! You are the winner!" << endl;
    } else if (player_score == computer_score) {
        cout << "It's a tie game!" << endl;
    } else {
        cout << "Sorry, the computer won." << endl;
    }
}
```



# What now?

Now, we need to create a main function, `gameLoop(),` which manages the game’s flow. It takes `rounds` as a parameter and runs the game for the total number of rounds using the `for` loop.

These are the functions that we created in our game:

* `displayIntroductionAndRules()`

* `getRound()`

* `getPlayerChoice()`

* `generateComputerChoice()`

* `determineWinner()`

* `endGame()`

Let’s use these functions in the `gameLoop()` function and set up the game flow.

# Try it yourself

Write your code in the code widget below and click the “Run” button to execute your code. 

If you’re unsure how to do this, click the “Show Hint” button.

Learn to set up the main function using all functions.

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Joining the Dots

What we have