C++ Text Game (Number Guess)

#include <iostream>
#include <Windows.h>
#include <string>
#include <random>
#include <ctime>
#include <stdlib.h>


using namespace std;

void scl() {
    system("cls");
}

class AllColors {
    public:
        void ColorChoices() {
            std::cout << ") Red" << endl;
            std::cout << ") Green" << endl;
            std::cout << ") Aqua" << endl;
            std::cout << ") White" << endl;
            std::cout << ") Default" << endl;
            std::cout << ") Menu\n" << endl;
        }
};

int main() {
    system("color d");
    ShowWindow(GetConsoleWindow(), SW_MAXIMIZE);
    SetConsoleTitle("Number Guess V1 Development Build");
    int menu();
    menu();

    return 0;
}

int menu() {
    string _menu_choice;

    std::cout << "Play Game" << endl;
    std::cout << "Settings" << endl;
    std::cout << "Exit\n" << endl;
    std::cout << "> ";

    cin >> _menu_choice;

    if (_menu_choice == "PLAY" || _menu_choice == "Play" || _menu_choice == "play"
        || _menu_choice == "GAME" || _menu_choice == "Game" || _menu_choice == "game") {
        int playGame();
        playGame();
    }
    else if (_menu_choice == "SETTINGS" || _menu_choice == "Settings" || _menu_choice == "settings") {
        scl();
        void settings();
        settings();
    }
    else if (_menu_choice == "EXIT" || _menu_choice == "Exit" || _menu_choice == "exit"
        || _menu_choice == "QUIT" || _menu_choice == "Quit" || _menu_choice == "quit") {
        scl();
        void quit();
        quit();
    }
    else {
        scl();
        int menu();
        menu();
    }

    return 0;
}

int playGame() {
    scl();
    string PlayGameOption;
    std::cout << ") Easy" << endl;
    std::cout << ") Medium" << endl;
    std::cout << ") Hard" << endl;
    std::cout << ") Menu\n" << endl;
    std::cout << "> ";

    cin >> PlayGameOption;

    if (PlayGameOption == "EASY" || PlayGameOption == "Easy" || PlayGameOption == "easy") {
        scl();
        int playGameEasy();
        playGameEasy();
    }
    else {
        scl();
        int playGame();
        playGame();
    }
    return 0;
}

int playGameEasy() {
    int NumberEasy;
    default_random_engine RandomEngineForEasyMode(time(NULL));
    uniform_int_distribution<int> EasyMode(1, 20);
    std::cout << "Enter 0 To Exit..." << endl;
    std::cout << "--Press Any Key To Continue--" << endl;
    system("pause >nul");
    scl();

    Easy:
    std::cout << "Guess the number from 1 to 20.\n" << endl;
    cin >> NumberEasy;

    if (GetAsyncKeyState('0') & 0x8000) {
        scl();
        int playGame();
        playGame();
    }
    if (NumberEasy == (EasyMode(RandomEngineForEasyMode))) {
        scl();
        std::cout << "Correct!" << endl;
        std::cout << "--Press Any Key To Continue--" << endl;
        system("pause >nul");
        scl();
        int playGame();
        playGame();
    }
    else {
        scl();
        goto Easy;
    }
    return 0;
}

void color() {
    scl();
    string ColorChoice;

    AllColors Colors;
    Colors.ColorChoices();
    std::cout << endl;
    std::cout << "> ";

    cin >> ColorChoice;

    if (ColorChoice == "RED" || ColorChoice == "Red" || ColorChoice == "red") {
        system("color c");
        scl();
        void settings();
        settings();
    }
    else if (ColorChoice == "GREEN" || ColorChoice == "Green" || ColorChoice == "green") {
        system("color a");
        scl();
        void settings();
        settings();
    }
    else if (ColorChoice == "AQUA" || ColorChoice == "Aqua" || ColorChoice == "aqua") {
        system("color b");
        scl();
        void settings();
        settings();
    }
    else if (ColorChoice == "WHITE" || ColorChoice == "White" || ColorChoice == "white") {
        system("color f");
        scl();
        void settings();
        settings();
    }
    else if (ColorChoice == "DEFAULT" || ColorChoice == "Default" || ColorChoice == "default") {
        system("color a");
        scl();
        void settings();
        settings();
    }
    else if (ColorChoice == "BACK" || ColorChoice == "Back" || ColorChoice == "back") {
        scl();
        void settings();
        settings();
    }
    else {
        scl();
        void color();
        color();
    }
}

void settings() {
    string _setting_choice;

    std::cout << ") Color" << endl;
    std::cout << ") Menu\n" << endl;
    std::cout << "> ";
    cin >> _setting_choice;

    if (_setting_choice == "COLOR" || _setting_choice == "Color" || _setting_choice == "color") {
        void color();
        color();
    }
    else if (_setting_choice == "MENU" || _setting_choice == "Menu" || _setting_choice == "menu") {
        scl();
        int menu();
        menu();
    }
    else {
        scl();
        void settings();
        settings();
    }
}

void quit() {
    string _quit_sure;

    std::cout << "Are you sure you want to quit? (Y\N)" << endl;
    cin >> _quit_sure;

    if (_quit_sure == "Y" || _quit_sure == "y") {
        exit(0);
    }
    else {
        scl();
        int menu();
        menu();
    }
}