// C++ defination
enum Suit {Club, Diamond, Heart, Spade};

// Java defination 
public enum Suit {
    Club(0), Diamond(1), Heart(2), Spade(3);
    private int _value;
    private Suit(int v) { _value = v; };
    public int getValue() { return _value; };
    public static Suit getSuitFromValue(int value) {}; // ...
};

enum Suit { Diamonds, Hearts, Clubs, Spades }; // 0, 1, 2, 3

enum Suit { Diamonds = 1, Hearts, Clubs, Spades }; // 1, 2, 3, 4

enum Suit { Diamonds = 5, Hearts, Clubs = 4, Spades }; // 5, 6, 4, 5

enum Color { red, green, blue };                    // plain enum 
enum Card { red_card, green_card, yellow_card };    // another plain enum 
enum class Animal { dog, deer, cat, bird, human };  // enum class
enum class Mammal { kangaroo, deer, human };        // another enum class

void fun() {

    // examples of bad use of plain enums:
    Color color = Color::red;
    Card card = Card::green_card;

    int num = color;    // no problem

    if (color == Card::red_card) // no problem (bad)
        cout << "bad" << endl;

    if (card == Color::green)   // no problem (bad)
        cout << "bad" << endl;

    // examples of good use of enum classes (safe)
    Animal a = Animal::deer;
    Mammal m = Mammal::deer;

    int num2 = a;   // error
    if (m == a)         // error (good)
        cout << "bad" << endl;

    if (a == Mammal::deer) // error (good)
        cout << "bad" << endl;

}