CODEWITHSUNDEEP
c++classreturnsetter
CheetahBongos
CheetahBongos

Reputation: 197

Changing private variable of object in a vector

I am trying to change the value of an int variable in my Card class shown below:

class Card {
  public:
    enum Suits {diamond, heart, club, spade};
    Card (int _rank, Suits _suit) : rank{_rank}, suit{_suit} {}
    int getRank();
    void changeRank(int change);

  private:
    int rank;
    Suits suit;
};

card.cpp:

int Card::getRank() {
  return rank;
}

void Card::changeRank(int change) {
    rank = change;
}

Here is the Player class:

class Player {
  private:
    vector<Card> playerHand;

  public:
    Card getCard(int index);
};

player.cpp:

Card Player::getCard(int index) {
    return playerHand[index];
}

Here is the dealer.cpp file that actually makes the call:

if (oneOrEleven == 11) {
    player.getCard(i).changeRank(11);
    cout << "The ace will have a value of 11" << endl;
}

This code is calling the method "changeRank()", it's just not changing the value of "rank" in the Card object.

What am I doing wrong?

Upvotes: 1

Views: 83

Answers (2)

Tuufless
Tuufless

Reputation: 11

This code is calling the method "changeRank()", it's just not changing the value of "rank" in the Card object.

Change the function declaration of getCard to return by reference, i.e:

Card& getCard(int index);

The way you have your function declaration right now, it is returning a Card object by value, and not by reference.

When you return by value, you are returning a copy of the object, and not the actual object itself.

Upvotes: 1

songyuanyao
songyuanyao

Reputation: 172964

You should change Player::getCard from return-by-value to return-by-reference. e.g.

Card& Player::getCard(int index) {
    return playerHand[index];
}

Ohterwise, you'll always modify on the returned copy, which has nothing to do with the original element in the vector.

Upvotes: 2

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