main.cpp

#include <iostream>
#include <random>
#include <thread>
#include <chrono>

using namespace std;

string acceptableReplayInputs[2] = {"Y", "N"};

namespace defaults {
    constexpr int minimumNumber = 1;
    constexpr int maximumNumber = 10;
}

bool gameRunning = true;

string makeUpper(string stringToConvert) {
    for (char &c : stringToConvert) {
        // Cast it to unsigned char first to avoid negative value issues (toupper expects this)
        const int upper = toupper(static_cast<unsigned char>(c));
        c = static_cast<char>(upper); // Convert each character to uppercase (back to a normal char)
    }

    return stringToConvert;
}

int RandomNumber() {
    random_device rd; // random_device gets a seed from the hardware of the pc every compilation
    mt19937 gen(rd()); // Use the mersenne-twister engine to generate the number with the rd seed
    uniform_int_distribution<> distribution(1,10); // Generate a range of ints, with an even distribution (equal amount of chance of being chosen)

    return distribution(gen); // Generate the random number with our engine, within our range
}

int ValidateIntegerInput() {
    int userInput;

    // Loop until the input is valid for the type (int)
    // Loop will only be entered if the type check fails

    while (true) {
        cout << "Enter a number between 1 and 10: ";

        while (!(cin >> userInput)) {
            // Input wasn't a valid int
            cout << "Invalid input, please type a number: ";

            cin.clear();
            cin.ignore(numeric_limits<streamsize>::max(), '\n');
        }

        // Input was an int, but outside the range
        if (userInput < defaults::minimumNumber || userInput > defaults::maximumNumber) {
            cout << "Number must be between " << defaults::minimumNumber <<  " and " << defaults::maximumNumber << "." << endl;
            continue;
        }

        // If we got here, its valid and in range
        break;
    }


    cout << "You entered: " << userInput << endl;
    return userInput;
}

bool isValidAnswer(const size_t listSize, string acceptableInputs[], const string& userAnswer) {
    for (int j=0; j < listSize; j++ ) {
        if (acceptableInputs[j] == userAnswer) {
            return true;
        }
    }

    return false;
}

void GameplayLoop() {
    cout << "I'm thinking of a number between " << defaults::minimumNumber << "and " << defaults::maximumNumber << "!" << endl;
    const int numberToGuess = RandomNumber();
    bool userHasGuessedCorrectly = false;
    int amountOfGuesses {0};

    while (!userHasGuessedCorrectly) {
        const int userGuess = ValidateIntegerInput();
        amountOfGuesses++;

        if (userGuess == numberToGuess) {
            cout << "Correct! You got it in " << amountOfGuesses << " guesses.";
            userHasGuessedCorrectly = true;
        } else {
            cout << "Sorry, try again.\n";
        }
    }

    string playAgainAnswer;
    while (true) {
        cout << "Do you want to play again? (Y/N)";
        cin >> playAgainAnswer;
        playAgainAnswer = makeUpper(playAgainAnswer);

        if (isValidAnswer(size(acceptableReplayInputs), acceptableReplayInputs, playAgainAnswer)) {
            // Valid response
            break;
        }

        cout << "Please enter either Y or N.\n";
    }

    if (playAgainAnswer == "Y") {
        GameplayLoop();
    } else {
        gameRunning = false;
    }
}

int main() {

    while (gameRunning) {
        GameplayLoop();
    }

    cout << "Thanks for playing, goodbye!";
    // Wait a couple seconds before exiting
    this_thread::sleep_for(chrono::seconds(2));

    return 0;
}