MC明明 发表于 2020-3-18 20:40:24

void analyz_hand(void)函数中,第一、二for循环没看懂,read_cards函数是如何返回值的

/*********************************************************
* From C PROGRAMMING: A MODERN APPROACH, Second Edition *
* By K. N. King                                       *
* Copyright (c) 2008, 1996 W. W. Norton & Company, Inc. *
* All rights reserved.                                  *
* This program may be freely distributed for class use, *
* provided that this copyright notice is retained.      *
*********************************************************/

/* poker.c (Chapter 10, page 233) */
/* Classifies a poker hand */

#include <stdbool.h>   /* C99 only */
#include <stdio.h>
#include <stdlib.h>

#define NUM_RANKS 13
#define NUM_SUITS 4
#define NUM_CARDS 5

/* external variables */
int num_in_rank;
int num_in_suit;
bool straight, flush, four, three;
int pairs;   /* can be 0, 1, or 2 */

/* prototypes */
void read_cards(void);
void analyze_hand(void);
void print_result(void);

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

/**********************************************************
* read_cards: Reads the cards into the external          *
*             variables num_in_rank and num_in_suit;   *
*             checks for bad cards and duplicate cards.*
**********************************************************/
void read_cards(void)
{
bool card_exists;
char ch, rank_ch, suit_ch;
int rank, suit;
bool bad_card;
int cards_read = 0;

for (rank = 0; rank < NUM_RANKS; rank++) {
    num_in_rank = 0;
    for (suit = 0; suit < NUM_SUITS; suit++)
      card_exists = false;
}

for (suit = 0; suit < NUM_SUITS; suit++)
    num_in_suit = 0;

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 if (card_exists)
      printf("Duplicate card; ignored.\n");
    else {
      num_in_rank++;
      num_in_suit++;
      card_exists = true;
      cards_read++;
    }
}
}

/**********************************************************
* analyze_hand: Determines whether the hand contains a   *
*               straight, a flush, four-of-a-kind,       *
*               and/or three-of-a-kind; determines the   *
*               number of pairs; stores the results into *
*               the external variables straight, flush,*
*               four, three, and pairs.                  *
**********************************************************/
void analyze_hand(void)
{
int num_consec = 0;
int rank, suit;

straight = false;
flush = false;
four = false;
three = false;
pairs = 0;

/* check for flush */
for (suit = 0; suit < NUM_SUITS; suit++)
    if (num_in_suit == NUM_CARDS)
      flush = true;

/* check for straight */
rank = 0;
while (num_in_rank == 0) rank++;
for (; rank < NUM_RANKS && num_in_rank > 0; rank++)
    num_consec++;
if (num_consec == NUM_CARDS) {
    straight = true;
    return;
}

/* check for 4-of-a-kind, 3-of-a-kind, and pairs */
for (rank = 0; rank < NUM_RANKS; rank++) {
    if (num_in_rank == 4) four = true;
    if (num_in_rank == 3) three = true;
    if (num_in_rank == 2) pairs++;
}
}

/**********************************************************
* print_result: Prints the classification of the hand,   *
*               based on the values of the external      *
*               variables straight, flush, four, three,*
*               and pairs.                               *
**********************************************************/
void print_result(void)
{
if (straight && flush) printf("Straight flush");
else if (four)         printf("Four of a kind");
else if (three &&
         pairs == 1)   printf("Full house");
else if (flush)      printf("Flush");
else if (straight)   printf("Straight");
else if (three)      printf("Three of a kind");
else if (pairs == 2)   printf("Two pairs");
else if (pairs == 1)   printf("Pair");
else                   printf("High card");

printf("\n\n");
}

MC明明 发表于 2020-3-18 20:41:05

在线等待大佬出现解答{:10_256:}
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