Question

我正在努力更好地了解以下程序的工作原理。该程序旨在以随机顺序洗牌。

有人可以解释一些函数的细节以及代码的确切运作方式吗？我理解二维数组的使用，但是一些shuffle函数让我和最后一个print语句混淆：

printf( "%5s of %-8s%c", wFace[ column ], wSuit[ row ],card % 2 == 0 ? '\n':'\t' );

以下是代码：

  #include <stdio.h>
  #include <stdlib.h>
   #include <time.h>
   #define SUITS 4
   #define FACES 13
   #define CARDS 52
   // prototypes

 void shuffle( unsigned int wDeck[][ FACES ] ); // shuffling modifies wDeck
 void deal( unsigned int wDeck[][ FACES ], const char *wFace[],
 const char *wSuit[] ); // dealing doesn't modify the arrays

int main( void )
{

const char *suit[ SUITS ] =
 { "Hearts", "Diamonds", "Clubs", "Spades" };
 // initialize face array

 const char *face[ FACES ] =
 { "Ace", "Deuce", "Three", "Four",
 "Five", "Six", "Seven", "Eight",
 "Nine", "Ten", "Jack", "Queen", "King" };

 unsigned int deck[ SUITS ][ FACES ] = { 0 };

 srand( time( NULL ) ); // seed random-number generator


 shuffle( deck ); // shuffle the deck
 deal( deck, face, suit ); // deal the deck
 }


 /*SHUFFLE FUNCTION*/
 void shuffle( unsigned int wDeck[][ FACES ] ){

 size_t row;
 size_t column;
 size_t card;

 for ( card = 1; card <= CARDS; ++card ) {
  do {
  row = rand() % SUITS;
  column = rand() % FACES;
  } while( wDeck[ row ][ column ] != 0 );

  wDeck[ row ][ column ] = card;}}

  void deal( unsigned int wDeck[][ FACES ], const char *wFace[], 
  const char    *wSuit[] ){

 size_t card;
 size_t row;
 size_t column;

  for ( card = 1; card <= CARDS; ++card ) {

   for ( row = 0; row < SUITS; ++row ) {

     for ( column = 0; column < FACES; ++column ) {

     if ( wDeck[ row ][ column ] == card ) {

    printf( "%5s of %-8s%c", wFace[ column ], wSuit[ row ],
     card % 2 == 0 ? '\n' : '\t' ); // 2-column format
       }}}}}

Answer 1

shuffle函数的核心是

 for ( card = 1; card <= CARDS; ++card ) {
  do {
  row = rand() % SUITS;
  column = rand() % FACES;
  } while( wDeck[ row ][ column ] != 0 );
  wDeck[ row ][ column ] = card;}

它一直在猜测一张脸和一套西装，直到找到一个不在牌组中的组合，然后它将它分配给牌组中的下一张牌。

令人困惑的printf功能只会打印两列中的所有卡片，如Ken解释的那样。

卡洗牌程序的工作原理有什么好的解释？

1 个答案: