Question

我正在尝试将数组传递给函数并用信息填充它。这段代码来自于练习以倾斜C中的按位运算的基础，但是当解析为函数“filldeck”时，数组“deck”变得已损坏。到那里它按预期工作。

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

typedef unsigned char card;
typedef unsigned char pairs;

/* arrays for the names of things */
static char *suits[] = {"Hearts","Diamonds","Clubs","Spades"};
static char *values[]= {"Ace","Two","Three","Four","Five","Six",\
                    "Seven","Eight","Nine","Ten","Jack",\
                    "Queen","King"};
static char *colour[]= {"Black","Red"};

/* function prototypes */
void printcard(card c); /* Displays the value of a card*/

void printdeck(card deck[52]); /* prints an entire deck of cards*/

void filldeck(card deck[52]); /* Populates a deck of cards */

void shuffle(card deck[52]); /* Randomizes the order of cards */

int compareface(const void* c1,const void *c2); 
/* compares the face value of 2 cards, suitable to pass to qsort
as the fourth argument */

pairs findpairs(card *hand); /* finds any pairs in a hand */

int main()
{
    card deck[52],*deckp;
    card hands[5][5],handssorted[5][5];
    pairs numpairs[5],highest;
    int hand,cd,winner;

    srand(time(NULL));       /* seed the random number generator */

    /*populate and shuffle the deck */

    filldeck(deck);
    scanf("%*c*");
    printdeck(deck);
    scanf("%*c");
    shuffle(deck);
    printdeck(deck);
}

void filldeck(card deck[52])
{
    /* populate the deck here */
    int x = 0;
    //hearts
    for(int y = 64; y <=112;y += 4)
    {
        deck[0 + x] = y;
        x ++;
    }
    //diamonds
    for(int y = 1; y <=49;y += 4)
    {
        deck[0 + x] = y;
        x ++;
    }
    //clubs
    for(int y = 2; y <=50;y += 4)
    {
        deck[0 + x] = y;
        x ++;
    }
    //spades
    for(int y = 67; y <=115;y += 4)
    {
        deck[0 + x] = y;
        x ++;
    }
    printf("Deck filled");
    return;
}

Answer 1

函数filldeck()增加x超过51并使用它来索引deck[52]。这样，您就可以超越数组边界并调用未定义的行为。

数组内容消失

1 个答案: