Fix the card shuffle/draw algorithm. Patch only slightly

modified from that given by John Darrow in NetBSD PR 9651.

diff --git a/games/fish/fish.c b/games/fish/fish.c
index 5501e87..d65c0c6 100644 (file)
--- a/games/fish/fish.c
+++ b/games/fish/fish.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: fish.c,v 1.6 1999/09/25 15:52:19 pjanzen Exp $        */
+/*     $OpenBSD: fish.c,v 1.7 2000/04/08 12:18:25 pjanzen Exp $        */
 /*     $NetBSD: fish.c,v 1.3 1995/03/23 08:28:18 cgd Exp $     */
 
 /*-
@@ -47,7 +47,7 @@ static char copyright[] =
 #if 0
 static char sccsid[] = "@(#)fish.c     8.1 (Berkeley) 5/31/93";
 #else
-static char rcsid[] = "$OpenBSD: fish.c,v 1.6 1999/09/25 15:52:19 pjanzen Exp $";
+static char rcsid[] = "$OpenBSD: fish.c,v 1.7 2000/04/08 12:18:25 pjanzen Exp $";
 #endif
 #endif /* not lint */
 
@@ -66,6 +66,7 @@ static char rcsid[] = "$OpenBSD: fish.c,v 1.6 1999/09/25 15:52:19 pjanzen Exp $"
 #define        RANKS           13
 #define        HANDSIZE        7
 #define        CARDS           4
+#define        TOTCARDS        RANKS * CARDS
 
 #define        USER            1
 #define        COMPUTER        0
@@ -78,7 +79,8 @@ const char *const cards[] = {
 #define        PRC(card)       (void)printf(" %s", cards[card])
 
 int promode;
-int asked[RANKS], comphand[RANKS], deck[RANKS];
+int curcard;
+int asked[RANKS], comphand[RANKS], deck[TOTCARDS];
 int userasked[RANKS], userhand[RANKS];
 
 void   chkwinner __P((int, const int *));
@@ -173,7 +175,7 @@ usermove()
                        continue;
                if (buf[0] == '\n') {
                        (void)printf("%d cards in my hand, %d in the pool.\n",
-                           countcards(comphand), countcards(deck));
+                           countcards(comphand), curcard);
                        (void)printf("My books:");
                        (void)countbooks(comphand);
                        continue;
@@ -273,9 +275,7 @@ drawcard(player, hand)
 {
        int card;
 
-       while (deck[card = nrandom(RANKS)] == 0);
-       ++hand[card];
-       --deck[card];
+       ++hand[card = deck[--curcard]];
        if (player == USER || hand[card] == CARDS) {
                printplayer(player);
                (void)printf("drew %s", cards[card]);
@@ -426,19 +426,22 @@ countbooks(hand)
 void
 init()
 {
-       int i, rank;
-
-       for (i = 0; i < RANKS; ++i)
-               deck[i] = CARDS;
-       for (i = 0; i < HANDSIZE; ++i) {
-               while (!deck[rank = nrandom(RANKS)]);
-               ++userhand[rank];
-               --deck[rank];
+       int i, j, temp;
+
+       curcard = TOTCARDS;
+       for (i = 0; i < TOTCARDS; ++i)
+               deck[i] = i % RANKS;
+       for (i = 0; i < TOTCARDS - 1; ++i) {
+               j = nrandom(TOTCARDS-i);
+               if (j == 0)
+                       continue;
+               temp = deck[i];
+               deck[i] = deck[i+j];
+               deck[i+j] = temp;
        }
        for (i = 0; i < HANDSIZE; ++i) {
-               while (!deck[rank = nrandom(RANKS)]);
-               ++comphand[rank];
-               --deck[rank];
+               ++userhand[deck[--curcard]];
+               ++comphand[deck[--curcard]];
        }
 }