Question

How to perform multiple 5‑card draws from a shuffled 52‑card deck in C

Answer 1

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

/*
A standard deck of 52 playing cards consists of four suits:
spades (♠), hearts (♥), diamonds (♦), and clubs (♣).

Each suit contains 13 ranks:
Ace, 2, 3, 4, 5, 6, 7, 8, 9, 10, Jack, Queen, King.

Cards of spades and clubs are black, while hearts and diamonds are red.

Color is informational only — it does not affect shuffling or random selection.
*/

/*
    This program performs multiple draws of 5 random cards from a 52‑card deck
    WITHOUT duplicates across draws.

    It uses:
    - Arrays of strings to store ranks, suits, and the deck
    - Fisher–Yates shuffle for efficient randomization
    - srand(time(NULL)) for randomness
    - Functions for clean structure

    Algorithm:
    1. Build a full deck (52 cards)
    2. Shuffle the remaining deck before each draw
    3. Draw 5 cards
    4. Remove those cards from the deck
*/

#define DECK_SIZE 52
#define DRAW_SIZE 5

void buildDeck(char deck[][20], int *deckCount) {
    const char *ranks[] = {
        "2","3","4","5","6","7","8","9","10","J","Q","K","A"
    };
    const char *suits[] = {
        "Clubs", "Diamonds", "Hearts", "Spades"
    };

    int index = 0;

    for (int s = 0; s < 4; s++) {
        for (int r = 0; r < 13; r++) {
            snprintf(deck[index], 20, "%s of %s", ranks[r], suits[s]);
            index++;
        }
    }

    *deckCount = DECK_SIZE;
}

void shuffleDeck(char deck[][20], int deckCount) {
    for (int i = deckCount - 1; i > 0; i--) {
        int j = rand() % (i + 1);

        char temp[20];
        strcpy(temp, deck[i]);
        strcpy(deck[i], deck[j]);
        strcpy(deck[j], temp);
    }
}

void drawFive(char deck[][20], int *deckCount, int drawNumber) {
    printf("Draw #%d:\n", drawNumber);

    for (int i = 0; i < DRAW_SIZE; i++) {
        printf("  %s\n", deck[i]);
    }
    printf("\n");

    // Remove drawn cards by shifting the deck
    for (int i = DRAW_SIZE; i < *deckCount; i++) {
        strcpy(deck[i - DRAW_SIZE], deck[i]);
    }

    *deckCount -= DRAW_SIZE;
}

int main() {
    // Number of draws
    int draws = 3;

    char deck[DECK_SIZE][20];
    int deckCount = 0;

    srand((unsigned)time(NULL));

    // Build the deck
    buildDeck(deck, &deckCount);

    // Perform multiple draws (no duplicates)
    for (int i = 1; i <= draws; i++) {
        if (deckCount < DRAW_SIZE) {
            printf("Not enough cards left for draw #%d.\n", i);
            break;
        }

        shuffleDeck(deck, deckCount);
        drawFive(deck, &deckCount, i);
    }

    return 0;
}


/*
run:

Draw #1:
  5 of Hearts
  9 of Diamonds
  6 of Diamonds
  4 of Hearts
  3 of Spades

Draw #2:
  2 of Hearts
  8 of Diamonds
  K of Hearts
  A of Hearts
  J of Clubs

Draw #3:
  3 of Diamonds
  2 of Diamonds
  10 of Spades
  A of Diamonds
  10 of Hearts

*/

 

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