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Hey guys! I just wanted to do a simple walk-through of creating a card game in C++. Text based card games are some of the easiest games to program. They are great for beginner programmers! For this post, I will create the deck and shuffle it. This will be a great setup for implementing many card games that use a 52 card deck. I will code different games later in this series.

Planning out the code

To go about this, I will make 3 files. A header file, a file to hold my functions, and a file for main().

1. header (cards.h)
   • Create a class called Card
     • This will hold the attributes of one card (face value and suit)
2. functions (card_functions.cpp)
   • Create several functions
     • Create the deck --> set_deck()
     • Shuffle the deck --> shuffle_deck()
3. Main (cards_main.cpp)
   • Create an array of 52 Card objects
   • Call set_deck()
   • Call shuffle_deck()
   • print the deck before and after it is shuffled (the program doesn't have any other use at the moment)

Writing the code

Here is what I wrote...

cards.h

#ifndef CARDS_H
#define CARDS_H

class Card
{
    public:
        string face;
        string suit;
};

#endif

• Every Card object has two string members
  • face --> holds the face value
  • suit --> holds what suit the card is

cards_functions.cpp

#ifndef CARDS_FUNCTIONS_CPP
#define CARDS_FUNCTIONS_CPP

void set_deck(Card* deck)
{
    for(int x = 0; x < 13; x++)// all hearts
    {
        char number = x + 49;
        deck[x].suit = "hearts";
        if(x == 0)
            deck[x].face = "Ace";
        else if(x == 9)
            deck[x].face = "10";
        else if(x == 10)
            deck[x].face = "Jack";
        else if(x == 11)
            deck[x].face = "Queen";
        else if(x == 12)
            deck[x].face = "King";
        else
            deck[x].face = number;
    }
    for(int x = 0; x < 13; x++)// all diamonds
    {
        char number = x + 49;
        deck[x+13].suit = "diamonds";
        if(x == 0)
            deck[x+13].face = "Ace";
        else if(x == 9)
            deck[x+13].face = "10";
        else if(x == 10)
            deck[x+13].face = "Jack";
        else if(x == 11)
            deck[x+13].face = "Queen";
        else if(x == 12)
            deck[x+13].face = "King";
        else
            deck[x+13].face = number;
    }
    for(int x = 0; x < 13; x++)// all clubs
    {
        char number = x + 49;
        deck[x+26].suit = "clubs";
        if(x == 0)
            deck[x+26].face = "Ace";
        else if(x == 9)
            deck[x+26].face = "10";
        else if(x == 10)
            deck[x+26].face = "Jack";
        else if(x == 11)
            deck[x+26].face = "Queen";
        else if(x == 12)
            deck[x+26].face = "King";
        else
            deck[x+26].face = number;
    }
    for(int x = 0; x < 13; x++)// all spades
    {
        char number = x + 49;
        deck[x+39].suit = "spades";
        if(x == 0)
            deck[x+39].face = "Ace";
        else if(x == 9)
            deck[x+39].face = "10";
        else if(x == 10)
            deck[x+39].face = "Jack";
        else if(x == 11)
            deck[x+39].face = "Queen";
        else if(x == 12)
            deck[x+39].face = "King";
        else
            deck[x+39].face = number;
    }
}

void shuffle_deck(Card* deck, int size)
{
    for(int x = 0; x < size; x++)
    {
        int swap = rand() % size;
        Card temp = deck[x];
        deck[x] = deck[swap];
        deck[swap] = temp;
    }
}

#endif

• set_deck() --> function that sets all values of a given Card array
  • deck --> the Card array
  • Every for loop sets the values of each card for one suit
  • number --> a character to hold the character values of x (only works for 1 - 9)
    • When 49 is added an integer from 0 - 9, this is the ASCII value for that number
    • in other words, this changes the integer value of x into its character equivalent
• shuffle_deck() --> function that shuffles a Card array given to it
  • deck --> the Card array
  • size --> the size of the Card array (shuffle_deck() will shuffle decks of a different size than 52 also)
  • swap --> a random number between 0 and size-1
    • this will be a random address for the each Card to swap with in the array
  • temp --> a temporary Card object to hold the value of deck[x]
  • swap the values of the two addresses

cards_main.cpp

#include <iostream>
#include <string>
#include <stdlib.h>
#include <time.h>

using namespace std;

#include "cards.h"
#include "cards_functions.cpp"


int main()
{
    Card deck[52];
    set_deck(deck);

// prints the deck
    for(int x = 0; x < 52; x++)
        cout << deck[x].face << " of " << deck[x].suit << endl;

    for(int x = 0; x < 30; x++)
        cout << "--";
    cout << endl;

    srand (time(NULL));
    shuffle_deck(deck, 52);

// prints the deck
    for(int x = 0; x < 52; x++)
        cout << deck[x].face << " of " << deck[x].suit << endl;

    return 0;
}

• place all of the includes and "using namespace std;" before the other files are included
• include cards.h and cards_functions.cpp
• main()
  • deck --> an array of 52 Card objects
  • call set_deck() and pass it deck
  • print the cards in order
  • call shuffle_deck() and hand in deck (and the size of 52)
  • print the shuffled deck

The output:

[cmw4026@omega cards]$ g++ cards_main.cpp
[cmw4026@omega cards]$ ./a.out
Ace of hearts
2 of hearts
3 of hearts
4 of hearts
5 of hearts
6 of hearts
7 of hearts
8 of hearts
9 of hearts
10 of hearts
Jack of hearts
Queen of hearts
King of hearts
Ace of diamonds
2 of diamonds
3 of diamonds
4 of diamonds
5 of diamonds
6 of diamonds
7 of diamonds
8 of diamonds
9 of diamonds
10 of diamonds
Jack of diamonds
Queen of diamonds
King of diamonds
Ace of clubs
2 of clubs
3 of clubs
4 of clubs
5 of clubs
6 of clubs
7 of clubs
8 of clubs
9 of clubs
10 of clubs
Jack of clubs
Queen of clubs
King of clubs
Ace of spades
2 of spades
3 of spades
4 of spades
5 of spades
6 of spades
7 of spades
8 of spades
9 of spades
10 of spades
Jack of spades
Queen of spades
King of spades
------------------------------------------------------------
7 of diamonds
2 of clubs
7 of clubs
7 of spades
Jack of clubs
8 of hearts
6 of clubs
King of clubs
10 of hearts
7 of hearts
4 of clubs
King of diamonds
3 of spades
10 of diamonds
Jack of spades
5 of diamonds
10 of spades
6 of diamonds
2 of spades
Jack of hearts
8 of diamonds
4 of diamonds
8 of clubs
6 of spades
Queen of spades
Ace of diamonds
5 of hearts
Queen of clubs
4 of spades
Ace of clubs
3 of clubs
2 of hearts
Queen of diamonds
5 of spades
9 of hearts
9 of diamonds
Ace of spades
King of hearts
3 of hearts
8 of spades
6 of hearts
10 of clubs
4 of hearts
Queen of hearts
Ace of hearts
5 of clubs
2 of diamonds
9 of spades
King of spades
3 of diamonds
Jack of diamonds
9 of clubs
[cmw4026@omega cards]$

• As you can see, the cards were shuffled nicely and very randomly.

That is it for this part. I will be implementing this code for actual card games in the future. Thanks for reading!

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