Card Shuffle Help

i need to shuffle an array of cards and simply print them in a simple order but i dont know where to go from here, please help.

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>


int main()
{
        char suit[4][0]={"Hearts", "Diamonds", "Spades", "Clubs"};
        char deck[51] {"H2", "H3", "H4", "H5", "H6", "H7", "H8", "H9", "H10", "HJ", "HQ", "HK", "HA",
              "D2", "D3", "D4", "D5", "D6", "D7", "D8", "D9", "D10", "DJ", "DQ", "DK", "DA",
              "S2", "S3", "S4", "S5", "S6", "S7", "S8", "S9", "S10", "SJ", "SQ", "SK", "SA",
              "C2", "C3", "C4", "C5", "C6", "C7", "C8", "C9", "C10", "CJ", "CQ" "CK", "CA"};
        int card;
       
       
_getch();
return 0;
}

---

FYI.

Most C compilers ignore white space, which means as a courtesy to us all, you can split long lines and make it multiple short lines.

And the last time I counted, there were 52 cards in a deck. ;)

Todd

To shuffle the deck you can swap positions in the array something like:

Code:

---

#include <stdlib.h>
#include<ctime.h>

int main()
{
    srand(time(NULL)); //Seed randomisation

    int deck[52];
    int i, temp, random;
    // Init deck
    for(i=0; i<52; i++)
        deck[i] = i;
    //Shuffle deck
    for(i=0; i<52; i++)
    {
        random = rand() % 52;
        temp = deck[ i ];
        deck[ i ] = deck[ random ];
        deck[ random ] = temp;
    }
}

---

Also you can use an integer value to hold the card. card value % 13 will get the rank and card value / 13 the suit. You could then get the relevant text using functions something like:

Code:

---

const char* GetSuit(Uint8 card)

{

    static const char *suit[] = {"Clubs", "Diamonds", "Hearts", "Spades"};

    return suit[card/13];   

}



const char* GetRank(Uint8 card)

{

    static const char *rank[] = {"Ace", "Two", "Three", "Four", "Five",

        "Six", "Seven", "Eight", "Nine", "Ten", "Jack", "Queen", "King"};

    return rank[card%13]; 

}

---

i have this but it doesnt seem to work i have to terminate the program and it comes up with lots of errors.

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include <stdlib.h>
#include <time.h>


int main()
{
    srand(time(NULL)); //Seed randomisation

    int deck[52];
    int i, temp, random;
    // Init deck
    for(i=0; i<52; i++)
        deck[i] = i;
    //Shuffle deck
    for(i=0; i<52; i++)
    {
        random = rand() % 52;
        temp = deck[ i ];
        deck[ i ] = deck[ random ];
        deck[ random ] = temp;
                printf("%s", deck[i]);
               
    }
return 0;
}

---

You can't print an integer using %s.

well heres the problem now, i can get it to display random numbers 1 through 52 but they should not repeat and also must be like a deck of cards with Jacks queens kings and aces

Your shuffle doesn't repeat numbers. You need to print outside the shuffle loop.

And everyone else is going to tell you what mike_g told you (about getting names), so I'm not even going to type it -- just look up and pretend I said it again, but louder this time.

from here how could i make it so each card takes a suit?

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include <stdlib.h>
#include <time.h>
#include <conio.h>


int main()
{
    srand(time(NULL)); //Seed randomisation

        char suit[4][0]= {"Hearts", "Spades", "Clubs", "Diamonds"}
        char rank[] = {"Ace", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Jack", "Queen", "King"};
            int deck[52];
               
    int i, temp, random;
    // Init deck
    for(i=0; i<52; i++)
        deck[i] = i;
    //Shuffle deck
    for(i=0; i<52; i++)
    {
        random = rand() % 52;
        temp = deck[i];
        deck[i] = deck[ random ];
        deck[ random ] = temp;               
               
    }
        printf("%d", deck[i]);
_getche();
return 0;
}

---

Quote:

---

Originally Posted by killmequick

from here how could i make it so each card takes a suit?

---

And everyone else is going to tell you what mike_g told you (about getting names), so I'm not even going to type it -- just look up and pretend I said it again, but even louder this time.

Quote:

---

Originally Posted by killmequick

Code:

---

char suit[4][0]= {"Hearts", "Spades", "Clubs", "Diamonds"}
char rank[] = {"Ace", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Jack", "Queen", "King"};

---

---

I don't expect either of those array declarations to work. The first declares an array of zero length which is not legal. The second declares an array of characters of unknown length instead of a 2D array of chars, or an array of pointers to chars.

so how would i write an array that works

i am not supposed to use constant characters with this program

Why not? contsant char would be more suitable since you wont want to be editing the content. Never the less, all you would have to do is copy the code from the functions I posted and remove the 'const' part. IE:

Code:

---

int main()
{
    char *suit[] = {"Clubs", "Diamonds", "Hearts", "Spades"};
}

---

The simplest way is to generate a randon number between 1 and 51, then split the array into
two at that point and then make a new array, with the botton half of the split above the top
half, then copy the result back to the original array. Repeat as necessary. That is how a real shuffle is done.
I guess you could mix this with 'fancy shuffles' where you split the pack in to to halfs and then merge them
into the order (for halfs 'a'' and 'b') a[0], b[0], a[1]], b[1], a[2], b[2], etc....



Or perhaps quicker and simpler, select a card at a random position and put it into a new array
in first position, then select another and put it the next position. If the card has already been selected use the first unselected card after it in the array. That is probably the fastest way. But is gets less effiecient towards the end.

I disagree - the algorithm mike suggested is the Knuth shuffle, which is a good shuffle because every card has an equal probability to be swapped with every other card. It's difficult to implement correctly, but I doubt it's any less efficient than what you've suggested. And in all honesty, I'd rather use a documented algorithm for shuffling. I don't think my feelings are that exceptional.