Thread: Array Help

I am having problems with this function. This is an exercise from the book "C Programming: A Modern Approach" Chapter 10.

Code:

void read_cards(void)
{
    char ch, rank_ch, suit_ch;
    int rank; 
    int suit = 0; 
    Bool bad_card;
    int cards_read = 0;

    /*	Sets all array elements to zero		*/
    for(rank = 0; rank < NUM_RANKS; rank++)
    {
	hand[rank][suit] = 0;

	for(suit = 0; suit < NUM_SUITS; suit++)
	    hand[rank][suit] = FALSE;
    }

    while (cards_read < NUM_CARDS) 
    {
	bad_card = FALSE;

	printf("Enter a card: ");

	rank_ch = getchar();
	switch (rank_ch) 
	{
	    case '0':           exit(EXIT_SUCCESS);
	    case '2':           rank = 0; break;
	    case '3':           rank = 1; break;
	    case '4':           rank = 2; break;
	    case '5':           rank = 3; break;
	    case '6':           rank = 4; break;
	    case '7':           rank = 5; break;
	    case '8':           rank = 6; break;
	    case '9':           rank = 7; break;
	    case 't': case 'T': rank = 8; break;
	    case 'j': case 'J': rank = 9; break;
	    case 'q': case 'Q': rank = 10; break;
	    case 'k': case 'K': rank = 11; break;
	    case 'a': case 'A': rank = 12; break;
	    default:            bad_card = TRUE;
	}

	suit_ch = getchar();
	switch (suit_ch) 
	{
	    case 'c': case 'C': suit = 0; break;
	    case 'd': case 'D': suit = 1; break;
	    case 'h': case 'H': suit = 2; break;
	    case 's': case 'S': suit = 3; break;
	    default:            bad_card = TRUE;
	}

	while ((ch = getchar()) != '\n')
	    if (ch != ' ') bad_card = TRUE;

	if (bad_card)
	    printf("Bad card; ignored.\n");
	else 
	{
	    hand[0][cards_read] = rank;
	    hand[1][cards_read] = suit;
	    printf("hand[1][%d] = %d. \n", cards_read, suit);
	    cards_read++;
	}
    }
    printf("Rank %d Suit %d. \n", hand[0][0], hand[1][0]);
    printf("Rank %d Suit %d. \n", hand[0][1], hand[1][1]);
    printf("Rank %d Suit %d. \n", hand[0][2], hand[1][2]);
    printf("Rank %d Suit %d. \n", hand[0][3], hand[1][3]);
    printf("Rank %d Suit %d. \n", hand[0][4], hand[1][4]);

}

This is the output I get from the command line.

Code:

Enter a card: 2h
hand[1][0] = 2. 
Enter a card: 3h
hand[1][1] = 2. 
Enter a card: 4h
hand[1][2] = 2. 
Enter a card: 5h
hand[1][3] = 2. 
Enter a card: 6h
hand[1][4] = 2. 
Rank 0 Suit 4. 
Rank 1 Suit 2. 
Rank 2 Suit 2. 
Rank 3 Suit 2. 
Rank 4 Suit 2.

The thing I am confused about is when I print out to screen the value stored in hand[1][0] why is it 4 and not 2? I have noticed that it changes value if I enter different cards.

Thanks for any help. If I need to provide any more information I will gladly do so.

Code:

hand[rank][suit] = 0;

It might be the beer talking, but I don't see where you have declared that array 'hand' - what is up with it?

Is your program huge? Might be useful to see the whole thing if it is not overly large.

Here is the top matter. I have not modified the analyze_hand and print_result functions to work with the changes requested in the exercise. They don't work with the changes I have made to the read_cards function. The part I am stuck on is before I even get that far. Here is the top matter.

Code:

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

#define NUM_RANKS 13
#define NUM_SUITS 4
#define NUM_CARDS 5
#define TRUE 1
#define FALSE 0

typedef int Bool;

Bool straight, flush, four, three;
int pairs;   /* can be 0, 1, or 2 */
int hand[NUM_RANKS][NUM_SUITS];

void read_cards(void);
void analyze_hand(void);
void print_result(void);

/********************************************************** 
 * main: Calls read_cards, analyze_hand, and print_result * 
 *       repeatedly.                                      * 
 **********************************************************/
int main()
{
    for (;;) 
    {          /* infinite loop */
	read_cards();
	analyze_hand();
	print_result();
    }

    return 0;
}

The exercise is to rewrite a example program. Ultimately I am trying to store the rank and suit of the cards in a poker hand in a 5x2 array. My thoughts were since there were 5 cards in the hand I would store the rank in hand[0][*] and the suits in hand[1][*]. Then do the comparisons needed to analyze the hand.

This is where I noticed the problem. I was trying to check for a flush (all suits should be the same) but it was not working. That is why I started looking at the values stored and noticed the value for hand[1][0] was not as it should be (2 in this case).

I just don't understand why it is not a 2. That is all. The printf statements are just me trying to figure out why this is the case. They will be removed later when I figure out my error.

I hope this helps clear things up.

quzah your points are good ones. The exercise explicitly says to use a 5x2 array. Yet another fact I left out... Sorry.

You guys are being more help than I am asking for. I am not complaining. This is a good thing.

Maybe I am not clear. I do not want help finishing up the program. I just want to understand why my assignment statements are not working for the array specifically with the hand[1][0] portion not being a 2 or any other suit as I expect. Is there something obvious I am missing here. I don't see where the value should change. To me it looks straight forward.

I just want to understand why the value changes for that array position and not any other for the suits i.e. hand[1][*]. I can not see the error in my logic.