Sidestepping limitation of variable length member of fixed array sizes

cards.c

#include <stdio.h>  // for printf
#include <string.h> // for strcmp

// Define a card
typedef struct card
{
    int value;      // This is an int, so it's storage size does not change
    char * name;    // This is a pointer, so it's storange size does not change
    int rule_change;
} card_t;

// Example:  
/*
card_t test = {1, "test", 0};
card_t test_ary[] = {{1, "test", 0}, {1, "test", 0}};
*/


// Define an array of card_t pointers
typedef card_t * cards_t[];

// Use a macro to save lots of typing
#define MKCARD(VAL, NAME) &(card_t){VAL, NAME, 0}

// Make the data an array of pointers to the data, the macro also adds defaults for us
#define CARD_INITIAL_VALUES {   MKCARD(2, "Two"),    MKCARD(3, "Three"), MKCARD(4, "Four"), MKCARD(5, "Five"),  MKCARD(6, "Six"),    MKCARD(7, "Seven"), \
                                MKCARD(8, "Eight") , MKCARD(9, "Nine") , MKCARD(10, "Ten"), MKCARD(11, "Jack"), MKCARD(12, "Queen"), MKCARD(13, "King"), MKCARD(14, "Ace") }


// Create storage - note it is not necessary that all the suits are the same!!
cards_t suit_spades = CARD_INITIAL_VALUES;
cards_t suit_clubs = CARD_INITIAL_VALUES;
cards_t suit_diamonds = CARD_INITIAL_VALUES;
cards_t suit_hearts = CARD_INITIAL_VALUES;

// Define a suit
typedef struct suit
{
    char       * name;
    unsigned     n_cards;           //  Information only structure does not depend on this
//    card_t  cards[N_CARDS]        //  We could say this but that would fix the number of cards in every game
    card_t    ** cards;             //  Instead pointer arrays make it more flexible and make little change to the code
} suit_t;

// Example:
/*
suit_t suit = {
    .name    = "Toy Cards",
    .n_cards = 3,
    .cards = (cards_t){  &(card_t){2, "duck"}, &(card_t){3, "goose"}, &(card_t){4,"eagle"}}
};
*/

// Instead of counting memory we are counting pointers
// That way each array of pointers can be different
#define COUNT_CARDS(SUIT) ((unsigned)(sizeof(SUIT)/sizeof(card_t *)))

suit_t mygame_deck[] = {
    {
        .name = "Spades",
        .n_cards = COUNT_CARDS(suit_spades),
        .cards = suit_spades
    }, {
        .name = "Clubs",
        .n_cards = COUNT_CARDS(suit_clubs),
        .cards = suit_clubs
    }, {
        .name = "Diamonds",
        .n_cards = COUNT_CARDS(suit_diamonds),
        .cards = suit_diamonds
    }, {
        .name = "Hearts",
        .n_cards = COUNT_CARDS(suit_hearts),
        .cards = suit_hearts
    }
};

// Here we count memory as each array member is always the same size
#define N_SUITS ((unsigned)(sizeof(mygame_deck)/sizeof(typeof(0[mygame_deck]))))

// Demonstrate we are not using const so our array are not fixed
int game_rule_change(char *card, char *suit, int new_value)
{
    for (unsigned isuit=0; isuit < N_SUITS; isuit++)
        for (unsigned icard = 0; icard < mygame_deck[isuit].n_cards; ++icard)
            if ( strcmp(mygame_deck[isuit].name, suit) == 0 && 
                 strcmp(mygame_deck[isuit].cards[icard]->name, card) == 0)
                {
                    mygame_deck[isuit].cards[icard]->value = new_value;
                    mygame_deck[isuit].cards[icard]->rule_change = 1;
                    return 1;
                }
    return 0;
}

int main(void)
{
    unsigned total_cards = 0;
    for (unsigned isuit=0; isuit < N_SUITS; isuit++)total_cards += mygame_deck[isuit].n_cards;

    printf("This game has %d suites\n", N_SUITS);
    printf("You should have %u cards in the game\n", total_cards);
    printf("\nList of cards:\n");

    game_rule_change("Five", "Hearts", 200);

    for (unsigned isuit=0; isuit < N_SUITS; isuit++)
    {
        printf("  Suit: %s (%u cards)\n", mygame_deck[isuit].name, mygame_deck[isuit].n_cards);
        for (unsigned icard = 0; icard < mygame_deck[isuit].n_cards; ++icard)
        {
            printf("     The card  \'%s of %s\'  has the value of %d%s\n",
                mygame_deck[isuit].cards[icard]->name,
                mygame_deck[isuit].name,
                mygame_deck[isuit].cards[icard]->value,
                mygame_deck[isuit].cards[icard]->rule_change?"  - The rules have changed!!":"");
        }
        printf("\n");
    }

    return 0;
}