Question

I’m having trouble with the deal function in a blackjack program I am writing. Can anyone see what is going on? When I try to print in main(), I get a segmentation fault.

Cheers.

MAIN FUNCTION

int main(void)
{
    int i, j, k, purse;
    card deck[52];
    card *head_d, *temp_d, *current_d = NULL, *last_d, *head_p, *temp_p, *current_p = NULL, *last_p;



make(deck);  //CREATES THE DECK
shuffle(deck); //SHUFFLES THE DECK
deal(deck, head_d, current_d, head_p, current_p)

for(i = 0; i < DECK_SIZE; i++)
    {
        printf("%d: %d %c\n", i + 1, deck[i].face, deck[i].suit);
    }

temp_p = head_p;
while(temp_p != NULL)
{
printf("%d %c\n", temp_p->face, temp_p->suit);
temp_p = temp_p->listp;
}

return(0);
}

FUNCTION deal()

  void deal(card x[DECK_SIZE], card *head_d, card *current_d, card *head_p, card *current_p)
    {

    int i;
    card *temp_p, *temp_d;

    for(i = 0; i < 4; i++)
    {
        if( i % 2 == 0)
        {
            temp_p = (card *)malloc(sizeof(card));
            temp_p->face = x[i].face;
            temp_p->suit = x[i].suit;

            if (current_p==NULL)
            {
                head_p=temp_p;
            }
            else
            {
                current_p->listp=temp_p;
            }
                current_p = temp_p;
                temp_p->listp = NULL;

        }
        else
        {
            temp_d=(card *)malloc(sizeof(card));
            temp_d->face = x[i].face;
            temp_d->suit = x[i].suit;

            if (current_d==NULL)
            {
                head_d=temp_d;
            }
            else
            {
                current_d->listp=temp_d;
            }
                current_d = temp_d;
                temp_d->listp = NULL;
        }
    }
}

Answer 1

The problem is that the arguments to the deal function is local, meaning when you change their value in the function, the variables used when calling the function will not be changed. You need to pass those arguments by reference:

void deal(card x[DECK_SIZE], card **head_d, card **current_d, card **head_p, card **current_p);

The do e.g.

*head_p=temp_p;

in the function to set the variables.

Call as

deal(deck, &head_d, &current_d, &head_p, &current_p);