garbage strings printed from a const char pointer array in C

1

I'm trying to print out slected strings from a const char pointer array but the text displayed is absolutely garbage. I am not sure what went wrong. I condensed the code down for easy read below:

#pragma once
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define HAND_CARDS 5 /* maximum number of cards any particular Hand */

typedef struct card {
    int suit;
    int face;
} Card;

typedef struct hand {
    struct card pHand[5];
    int hQuality;
} Hand;

void print_pHand(struct hand player, const char* suit[], const char* face[]);


int main(void)
{
    /* initialize memory arrays of suit and face, to be referenced through out the game */
    const char *suit[4] = {"Hearts", "Diamonds", "Clubs", "Spades"};
    const char *face[13] = {"Ace", "Deuce", "Three", "Four", "Five", "Six", "Seven", "Eight",
                            "Nine", "Ten", "Jack", "Queen", "King"};

    int deck[4][13] = { 0 };
    Hand pHuman = { 0 };

    print_pHand(pHuman, suit, face);
    return 0;
}

void print_pHand(struct hand player, const char* suit[], const char* face[])
{
    int f = 0, s = 0, i = 0;
    for (i = 0; i < HAND_CARDS; ++i) {
        s = player.pHand[i].suit;
        f = player.pHand[i].face;
        printf("[%s : %s]\t", suit[s], face[f]);
    }
}

I changed the printf() part and it still produced the same problem.

Unhandled exception at 0x79B81F4C (ucrtbased.dll) in PA7.exe:
0xC0000005: Access violation reading location 0xF485A8D3. occurred

enter image description here

Seems like there is memory access problem but I am not sure how to fix it.

Note: Assuming the cards have already been dealt randomly to each player, although I might have missed some important part. So for the full code, please look at my github here:

https://github.com/karln-create/PA7-5CDPoker

c
arrays
pointers
char
const
asked on Stack Overflow Apr 29, 2020 by karln-create • edited Apr 30, 2020 by karln-create

1 Answer

3

This line in your code,

printf("[%5s : %-8s%c", suit[s], face[f]);

is passing insufficient amount of arguments to printf(). As there are three '%' in your call, printf() expects another three arguments, not two. However, since printf() is implemented as a variadic function, it had no idea how many arguments you actually passed to it, so it managed to access some memory where your non-existent third argument would have occupied, causing the error.

answered on Stack Overflow Apr 30, 2020 by user12986714

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