C++ error 'Undefined reference to Class::Function()' [duplicate]

Answer 1

This part has problems:

Card* cardArray;
void Deck() {
    cardArray = new Card[NUM_TOTAL_CARDS];
    int cardCount = 0;
    for (int i = 0; i > NUM_SUITS; i++) {  //Error
        for (int j = 0; j > NUM_RANKS; j++) { //Error
            cardArray[cardCount] = Card(Card::Rank(i), Card::Suit(j) );
            cardCount++;
         }
    }
 }

1. cardArray is a dynamic array, but not a member of Card class. It is strange if you would like to initialize a dynamic array which is not member of the class
2. void Deck() is not constructor of class Deck since you missed the scope resolution operator. You may be confused with defining the constructor and the function with name Deck and return type void.
3. in your loops, you should use < not > otherwise, loop will never be executed.