class initialization in C++

Question

I tried to initialize an array of a class then use a loop to change the data members in each of the objects. I'm not sure how to get the values to stick, because after I changed the values, I tried to print a random object out and it's just the default values and not the changed values. Any help would be appreciated, Thanks!

#include <iostream>
#include <string>
#include <time.h>
using namespace std;

class card {
private:
    int rank;
    int suit;
////////////////////////////////////////////////////////////
public:
/////////////////////////////////////////////////////////////
// default constructor with initialization list
    card(int userRank = (2,3,4,5,6) , int userSuit=15)
    :rank(userRank), suit(userSuit){}
///////////////////////////////////////////////////////////
// function to validate user's rank choice.
int cardcheckRank(int pRank){
    while(pRank<2 || pRank>14)
    {
        cout << "Choose a playing card rank between 2-14, where 11=Jack, "
            "12=Queen, 13=King, 14=Ace"<<endl;
        cin >> pRank;
    }
    return pRank;
}

/////////////////////////////////////////////////////////////
// function to validate user's suit choice.
int cardcheckSuit(int pSuit){
while(pSuit<15 || pSuit>18)
{
   cout << "Choose a playing card suit "
    "between 15-18, where 15=Diamond, 16=Club, 17=Heart, 18=Spades.";                                  
cin >> pSuit;
    }
    return pSuit;
}

//////////////////////////////////////////////////////////////////
// functioin to get a card value from user.
void storeCard(int pRank, int pSuit){

    card(cardcheckRank(pRank),cardcheckSuit(pSuit) );
}

/////////////////////////////////////////////////////////////////
// translates 
string faceRank(int translateRank){
switch (translateRank) {
    case 2:
        return "Two";
    case 3:
        return "Three";
    case 4:
        return "Four";
    case 5:
        return "Five";
    case 6:
        return "Six";
    case 7:
        return "Seven";
    case 8:
        return "Eight";
    case 9:
        return "Nine";
    case 10:
        return "Ten";
    case 11:
        return "Jack";
    case 12:
        return "Queen";
    case 13:
        return "King";
    case 14:
        return "Ace";
    default: return "Invalid";
    }
}
///////////////////////////////////////////////////////////
// translate integer suit value into a word.
string faceSuit(int translateSuit){
switch (translateSuit){
    case 15:
        return "Diamonds";
        break;
    case 16:
        return "Clubs";
        break;
    case 17:
        return "Hearts";
        break;
    case 18:
        return "Spades";
        break;
    default: return "Invalid";
    }
}
///////////////////////////////////////////////////////
// Function to print the current card.
void printCard(){

    cout << "The rank of the card is ";
    cout << faceRank(rank);
    cout << " and the suit is " << faceSuit(suit) << "." << endl;
}
};  // End of card class.
//////////////////////////////////////////////////////
// main function.
int main()
{   
srand (time(NULL)); // initialize random seed.
card deck[52];

char choice = 'n';
int h = 0; // card number.

    for(int i = 15; i < 19; i++)
    {
        int y = i;
        for(int j =2; j < 15; j++)
        {
            int z = j;
            (deck [h]).storeCard(z,y);
            cout << "Card rank " << (deck [h]).faceRank(z);
            cout << ", suit " << (deck [h]).faceSuit(y) <<endl;
            ++h;
        }
    }

do{ 
    cout <<"Would user like to play?(y/n)"<<endl;
    cin >> choice;
    int ranNum = (rand()% 51 + 0);
    if(choice == 'y')
    {
        cout << "User: ";
        deck[7].printCard();
    }
}
while(choice == 'y');
return 0;
}

Something weird's going on in your constructor. Your default value for userRank is just 6. Later, you create a card object and throw it away. — Qaz
– Qaz, Commented Nov 24, 2013 at 21:06
I don't really understand, but I was trying to set a default value to just give the object something but intended to make the whole array a deck of cards, with each card being an object. — Davy2468
– Davy2468, Commented Nov 24, 2013 at 21:19

user4815162342 · Accepted Answer · 2013-11-24 21:46:00Z

1

Values are not sticking because your storeCard function doesn't really store the card, it creates a new card object and throws it away. If you really want to express this by invoking the card constructor, then assign the constructed object to the current one:

void storeCard(int pRank, int pSuit){
    *this = card(cardcheckRank(pRank),cardcheckSuit(pSuit) );
}

A more idiomatic approach would be for storeCard to directly modify the object's attributes, much like the constructor does:

void storeCard(int pRank, int pSuit){
  rank = cardcheckRank(pRank);
  suit = cardcheckSuit(pSuit);
}

edited Nov 24, 2013 at 21:46

answered Nov 24, 2013 at 21:22

user4815162342

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2 Comments

Davy2468 Over a year ago

Thank you, I tried your suggestion about using the idiomatic approach and the values are sticking now. Thanks again!

user4815162342 Over a year ago

@Davy2468 It's also important to realize why your implementation failed. Although a constructor looks like an ordinary function, you cannot just call it. Calling a constructor is interpreted as constructing a new object - and leaving it hanging in the air. Unless you assign it to something (as I did in the modified storeCard), it will disappear, or even be altogether eliminated by the optimizer.

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