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wump.c revision 1.19
      1 /*	$NetBSD: wump.c,v 1.19 2006/01/19 20:15:31 garbled Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1989, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  * All rights reserved.
      7  *
      8  * This code is derived from software contributed to Berkeley by
      9  * Dave Taylor, of Intuitive Systems.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  * 3. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #ifndef lint
     38 __COPYRIGHT("@(#) Copyright (c) 1989, 1993\n\
     39 	The Regents of the University of California.  All rights reserved.\n");
     40 #endif /* not lint */
     41 
     42 #ifndef lint
     43 #if 0
     44 static char sccsid[] = "@(#)wump.c	8.1 (Berkeley) 5/31/93";
     45 #else
     46 __RCSID("$NetBSD: wump.c,v 1.19 2006/01/19 20:15:31 garbled Exp $");
     47 #endif
     48 #endif /* not lint */
     49 
     50 /*
     51  * A very new version of the age old favorite Hunt-The-Wumpus game that has
     52  * been a part of the BSD distribution of Unix for longer than us old folk
     53  * would care to remember.
     54  */
     55 
     56 #include <err.h>
     57 #include <sys/types.h>
     58 #include <sys/file.h>
     59 #include <sys/wait.h>
     60 #include <stdio.h>
     61 #include <stdlib.h>
     62 #include <string.h>
     63 #include <time.h>
     64 #include <unistd.h>
     65 #include "pathnames.h"
     66 
     67 /* some defines to spec out what our wumpus cave should look like */
     68 
     69 #define	MAX_ARROW_SHOT_DISTANCE	6		/* +1 for '0' stopper */
     70 #define	MAX_LINKS_IN_ROOM	25		/* a complex cave */
     71 
     72 #define	MAX_ROOMS_IN_CAVE	250
     73 #define	ROOMS_IN_CAVE		20
     74 #define	MIN_ROOMS_IN_CAVE	10
     75 
     76 #define	LINKS_IN_ROOM		3
     77 #define	NUMBER_OF_ARROWS	5
     78 #define	PIT_COUNT		3
     79 #define	BAT_COUNT		3
     80 
     81 #define	EASY			1		/* levels of play */
     82 #define	HARD			2
     83 
     84 /* some macro definitions for cleaner output */
     85 
     86 #define	plural(n)	(n == 1 ? "" : "s")
     87 
     88 /* simple cave data structure; +1 so we can index from '1' not '0' */
     89 struct room_record {
     90 	int tunnel[MAX_LINKS_IN_ROOM];
     91 	int has_a_pit, has_a_bat;
     92 } cave[MAX_ROOMS_IN_CAVE+1];
     93 
     94 /*
     95  * global variables so we can keep track of where the player is, how
     96  * many arrows they still have, where el wumpo is, and so on...
     97  */
     98 int player_loc = -1;			/* player location */
     99 int wumpus_loc = -1;			/* The Bad Guy location */
    100 int level = EASY;			/* level of play */
    101 int arrows_left;			/* arrows unshot */
    102 
    103 #ifdef DEBUG
    104 int debug = 0;
    105 #endif
    106 
    107 int pit_num = PIT_COUNT;		/* # pits in cave */
    108 int bat_num = BAT_COUNT;		/* # bats */
    109 int room_num = ROOMS_IN_CAVE;		/* # rooms in cave */
    110 int link_num = LINKS_IN_ROOM;		/* links per room  */
    111 int arrow_num = NUMBER_OF_ARROWS;	/* arrow inventory */
    112 
    113 char answer[20];			/* user input */
    114 
    115 int	bats_nearby(void);
    116 void	cave_init(void);
    117 void	clear_things_in_cave(void);
    118 void	display_room_stats(void);
    119 int	gcd(int, int);
    120 int	getans(const char *);
    121 void	initialize_things_in_cave(void);
    122 void	instructions(void);
    123 int	int_compare(const void *, const void *);
    124 void	jump(int);
    125 void	kill_wump(void);
    126 int	main(int, char **);
    127 int	move_to(const char *);
    128 void	move_wump(void);
    129 void	no_arrows(void);
    130 void	pit_kill(void);
    131 int	pit_nearby(void);
    132 void	pit_survive(void);
    133 int	shoot(char *);
    134 void	shoot_self(void);
    135 int	take_action(void);
    136 void	usage(void) __attribute__((__noreturn__));
    137 void	wump_kill(void);
    138 int	wump_nearby(void);
    139 
    140 int
    141 main(argc, argv)
    142 	int argc;
    143 	char **argv;
    144 {
    145 	int c, e=0;
    146 
    147 	/* Revoke setgid privileges */
    148 	setgid(getgid());
    149 
    150 #ifdef DEBUG
    151 	while ((c = getopt(argc, argv, "a:b:hp:r:t:d")) != -1)
    152 #else
    153 	while ((c = getopt(argc, argv, "a:b:hp:r:t:")) != -1)
    154 #endif
    155 		switch (c) {
    156 		case 'a':
    157 			arrow_num = atoi(optarg);
    158 			break;
    159 		case 'b':
    160 			bat_num = atoi(optarg);
    161 			break;
    162 #ifdef DEBUG
    163 		case 'd':
    164 			debug = 1;
    165 			break;
    166 #endif
    167 		case 'h':
    168 			level = HARD;
    169 			break;
    170 		case 'p':
    171 			pit_num = atoi(optarg);
    172 			break;
    173 		case 'r':
    174 			room_num = atoi(optarg);
    175 			if (room_num < MIN_ROOMS_IN_CAVE) {
    176 				(void)fprintf(stderr,
    177 	"No self-respecting wumpus would live in such a small cave!\n");
    178 				exit(1);
    179 			}
    180 			if (room_num > MAX_ROOMS_IN_CAVE) {
    181 				(void)fprintf(stderr,
    182 	"Even wumpii can't furnish caves that large!\n");
    183 				exit(1);
    184 			}
    185 			break;
    186 		case 't':
    187 			link_num = atoi(optarg);
    188 			if (link_num < 2) {
    189 				(void)fprintf(stderr,
    190 	"Wumpii like extra doors in their caves!\n");
    191 				exit(1);
    192 			}
    193 			break;
    194 		case '?':
    195 		default:
    196 			usage();
    197 	}
    198 
    199 	if (link_num > MAX_LINKS_IN_ROOM ||
    200 	    link_num > room_num - (room_num / 4)) {
    201 		(void)fprintf(stderr,
    202 "Too many tunnels!  The cave collapsed!\n(Fortunately, the wumpus escaped!)\n");
    203 		exit(1);
    204 	}
    205 
    206 	if (level == HARD) {
    207 		bat_num += ((random() % (room_num / 2)) + 1);
    208 		pit_num += ((random() % (room_num / 2)) + 1);
    209 	}
    210 
    211 	if (bat_num > room_num / 2) {
    212 		(void)fprintf(stderr,
    213 "The wumpus refused to enter the cave, claiming it was too crowded!\n");
    214 		exit(1);
    215 	}
    216 
    217 	if (pit_num > room_num / 2) {
    218 		(void)fprintf(stderr,
    219 "The wumpus refused to enter the cave, claiming it was too dangerous!\n");
    220 		exit(1);
    221 	}
    222 
    223 	instructions();
    224 	cave_init();
    225 
    226 	/* and we're OFF!  da dum, da dum, da dum, da dum... */
    227 	(void)printf(
    228 "\nYou're in a cave with %d rooms and %d tunnels leading from each room.\n\
    229 There are %d bat%s and %d pit%s scattered throughout the cave, and your\n\
    230 quiver holds %d custom super anti-evil Wumpus arrows.  Good luck.\n",
    231 	    room_num, link_num, bat_num, plural(bat_num), pit_num,
    232 	    plural(pit_num), arrow_num);
    233 
    234 	for (;;) {
    235 		clear_things_in_cave();
    236 		initialize_things_in_cave();
    237 		arrows_left = arrow_num;
    238 		do {
    239 			display_room_stats();
    240 			(void)printf("Move or shoot? (m-s) ");
    241 			(void)fflush(stdout);
    242 			if (!fgets(answer, sizeof(answer), stdin)) {
    243 				e=2;
    244 				break;
    245 			}
    246 		} while (!(e = take_action()));
    247 
    248 		if (e == 2 || !getans("\nCare to play another game? (y-n) "))
    249 			exit(0);
    250 		if (getans("In the same cave? (y-n) ") == 0)
    251 			cave_init();
    252 	}
    253 	/* NOTREACHED */
    254 	return (0);
    255 }
    256 
    257 void
    258 display_room_stats()
    259 {
    260 	int i;
    261 
    262 	/*
    263 	 * Routine will explain what's going on with the current room, as well
    264 	 * as describe whether there are pits, bats, & wumpii nearby.  It's
    265 	 * all pretty mindless, really.
    266 	 */
    267 	(void)printf(
    268 "\nYou are in room %d of the cave, and have %d arrow%s left.\n",
    269 	    player_loc, arrows_left, plural(arrows_left));
    270 
    271 	if (bats_nearby())
    272 		(void)printf("*rustle* *rustle* (must be bats nearby)\n");
    273 	if (pit_nearby())
    274 		(void)printf("*whoosh* (I feel a draft from some pits).\n");
    275 	if (wump_nearby())
    276 		(void)printf("*sniff* (I can smell the evil Wumpus nearby!)\n");
    277 
    278 	(void)printf("There are tunnels to rooms %d, ",
    279 	   cave[player_loc].tunnel[0]);
    280 
    281 	for (i = 1; i < link_num - 1; i++)
    282 		if (cave[player_loc].tunnel[i] <= room_num)
    283 			(void)printf("%d, ", cave[player_loc].tunnel[i]);
    284 	(void)printf("and %d.\n", cave[player_loc].tunnel[link_num - 1]);
    285 }
    286 
    287 int
    288 take_action()
    289 {
    290 	/*
    291 	 * Do the action specified by the player, either 'm'ove, 's'hoot
    292 	 * or something exceptionally bizarre and strange!  Returns 1
    293 	 * iff the player died during this turn, otherwise returns 0.
    294 	 */
    295 	switch (*answer) {
    296 		case 'M':
    297 		case 'm':			/* move */
    298 			return(move_to(answer + 1));
    299 		case 'S':
    300 		case 's':			/* shoot */
    301 			return(shoot(answer + 1));
    302 		case 'Q':
    303 		case 'q':
    304 		case 'x':
    305 			exit(0);
    306 		case '\n':
    307 			return(0);
    308 		}
    309 	if (random() % 15 == 1)
    310 		(void)printf("Que pasa?\n");
    311 	else
    312 		(void)printf("I don't understand!\n");
    313 	return(0);
    314 }
    315 
    316 int
    317 move_to(room_number)
    318 	const char *room_number;
    319 {
    320 	int i, just_moved_by_bats, next_room, tunnel_available;
    321 
    322 	/*
    323 	 * This is responsible for moving the player into another room in the
    324 	 * cave as per their directions.  If room_number is a null string,
    325 	 * then we'll prompt the user for the next room to go into.   Once
    326 	 * we've moved into the room, we'll check for things like bats, pits,
    327 	 * and so on.  This routine returns 1 if something occurs that kills
    328 	 * the player and 0 otherwise...
    329 	 */
    330 	tunnel_available = just_moved_by_bats = 0;
    331 	next_room = atoi(room_number);
    332 
    333 	/* crap for magic tunnels */
    334 	if (next_room == room_num + 1 &&
    335 	    cave[player_loc].tunnel[link_num-1] != next_room)
    336 		++next_room;
    337 
    338 	while (next_room < 1 || next_room > room_num + 1) {
    339 		if (next_room < 0 && next_room != -1)
    340 (void)printf("Sorry, but we're constrained to a semi-Euclidean cave!\n");
    341 		if (next_room > room_num + 1)
    342 (void)printf("What?  The cave surely isn't quite that big!\n");
    343 		if (next_room == room_num + 1 &&
    344 		    cave[player_loc].tunnel[link_num-1] != next_room) {
    345 			(void)printf("What?  The cave isn't that big!\n");
    346 			++next_room;
    347 		}
    348 		(void)printf("To which room do you wish to move? ");
    349 		(void)fflush(stdout);
    350 		if (!fgets(answer, sizeof(answer), stdin))
    351 			return(1);
    352 		next_room = atoi(answer);
    353 	}
    354 
    355 	/* now let's see if we can move to that room or not */
    356 	tunnel_available = 0;
    357 	for (i = 0; i < link_num; i++)
    358 		if (cave[player_loc].tunnel[i] == next_room)
    359 			tunnel_available = 1;
    360 
    361 	if (!tunnel_available) {
    362 		(void)printf("*Oof!*  (You hit the wall)\n");
    363 		if (random() % 6 == 1) {
    364 (void)printf("Your colorful comments awaken the wumpus!\n");
    365 			move_wump();
    366 			if (wumpus_loc == player_loc) {
    367 				wump_kill();
    368 				return(1);
    369 			}
    370 		}
    371 		return(0);
    372 	}
    373 
    374 	/* now let's move into that room and check it out for dangers */
    375 	if (next_room == room_num + 1)
    376 		jump(next_room = (random() % room_num) + 1);
    377 
    378 	player_loc = next_room;
    379 	for (;;) {
    380 		if (next_room == wumpus_loc) {		/* uh oh... */
    381 			wump_kill();
    382 			return(1);
    383 		}
    384 		if (cave[next_room].has_a_pit) {
    385 			if (random() % 12 < 2) {
    386 				pit_survive();
    387 				return(0);
    388 			} else {
    389 				pit_kill();
    390 				return(1);
    391 			}
    392 		}
    393 
    394 		if (cave[next_room].has_a_bat) {
    395 			(void)printf(
    396 "*flap*  *flap*  *flap*  (humongous bats pick you up and move you%s!)\n",
    397 			    just_moved_by_bats ? " again": "");
    398 			next_room = player_loc = (random() % room_num) + 1;
    399 			just_moved_by_bats = 1;
    400 		}
    401 
    402 		else
    403 			break;
    404 	}
    405 	return(0);
    406 }
    407 
    408 int
    409 shoot(room_list)
    410 	char *room_list;
    411 {
    412 	int chance, next, roomcnt;
    413 	int j, arrow_location, link, ok;
    414 	char *p;
    415 
    416 	/*
    417 	 * Implement shooting arrows.  Arrows are shot by the player indicating
    418 	 * a space-separated list of rooms that the arrow should pass through;
    419 	 * if any of the rooms they specify are not accessible via tunnel from
    420 	 * the room the arrow is in, it will instead fly randomly into another
    421 	 * room.  If the player hits the wumpus, this routine will indicate
    422 	 * such.  If it misses, this routine will *move* the wumpus one room.
    423 	 * If it's the last arrow, the player then dies...  Returns 1 if the
    424 	 * player has won or died, 0 if nothing has happened.
    425 	 */
    426 	arrow_location = player_loc;
    427 	for (roomcnt = 1;; ++roomcnt, room_list = NULL) {
    428 		if (!(p = strtok(room_list, " \t\n"))) {
    429 			if (roomcnt == 1) {
    430 				(void)printf(
    431 			"The arrow falls to the ground at your feet!\n");
    432 				return(0);
    433 			} else
    434 				break;
    435 		}
    436 		if (roomcnt > 5) {
    437 			(void)printf(
    438 "The arrow wavers in its flight and and can go no further!\n");
    439 			break;
    440 		}
    441 		next = atoi(p);
    442 		for (j = 0, ok = 0; j < link_num; j++)
    443 			if (cave[arrow_location].tunnel[j] == next)
    444 				ok = 1;
    445 
    446 		if (ok) {
    447 			if (next > room_num) {
    448 				(void)printf(
    449 "A faint gleam tells you the arrow has gone through a magic tunnel!\n");
    450 				arrow_location = (random() % room_num) + 1;
    451 			} else
    452 				arrow_location = next;
    453 		} else {
    454 			link = (random() % link_num);
    455 			if (link == player_loc)
    456 				(void)printf(
    457 "*thunk*  The arrow can't find a way from %d to %d and flys back into\n\
    458 your room!\n",
    459 				    arrow_location, next);
    460 			else if (cave[arrow_location].tunnel[link] > room_num)
    461 				(void)printf(
    462 "*thunk*  The arrow flys randomly into a magic tunnel, thence into\n\
    463 room %d!\n",
    464 				    cave[arrow_location].tunnel[link]);
    465 			else
    466 				(void)printf(
    467 "*thunk*  The arrow can't find a way from %d to %d and flys randomly\n\
    468 into room %d!\n",
    469 				    arrow_location, next,
    470 				    cave[arrow_location].tunnel[link]);
    471 			arrow_location = cave[arrow_location].tunnel[link];
    472 			break;
    473 		}
    474 		chance = random() % 10;
    475 		if (roomcnt == 3 && chance < 2) {
    476 			(void)printf(
    477 "Your bowstring breaks!  *twaaaaaang*\n\
    478 The arrow is weakly shot and can go no further!\n");
    479 			break;
    480 		} else if (roomcnt == 4 && chance < 6) {
    481 			(void)printf(
    482 "The arrow wavers in its flight and and can go no further!\n");
    483 			break;
    484 		}
    485 	}
    486 
    487 	/*
    488 	 * now we've gotten into the new room let us see if El Wumpo is
    489 	 * in the same room ... if so we've a HIT and the player WON!
    490 	 */
    491 	if (arrow_location == wumpus_loc) {
    492 		kill_wump();
    493 		return(1);
    494 	}
    495 
    496 	if (arrow_location == player_loc) {
    497 		shoot_self();
    498 		return(1);
    499 	}
    500 
    501 	if (!--arrows_left) {
    502 		no_arrows();
    503 		return(1);
    504 	}
    505 
    506 	{
    507 		/* each time you shoot, it's more likely the wumpus moves */
    508 		static int lastchance = 2;
    509 
    510 		if (random() % (level == EASY ? 12 : 9) < (lastchance += 2)) {
    511 			move_wump();
    512 			if (wumpus_loc == player_loc)
    513 				wump_kill();
    514 			lastchance = random() % 3;
    515 
    516 		}
    517 	}
    518 	return(0);
    519 }
    520 
    521 int
    522 gcd(a, b)
    523 	int a, b;
    524 {
    525 	int r;
    526 
    527 	r = a % b;
    528 	if (r == 0)
    529 		return (b);
    530 	return (gcd(b, r));
    531 }
    532 
    533 void
    534 cave_init()
    535 {
    536 	int i, j, k, link;
    537 	int delta;
    538 
    539 	/*
    540 	 * This does most of the interesting work in this program actually!
    541 	 * In this routine we'll initialize the Wumpus cave to have all rooms
    542 	 * linking to all others by stepping through our data structure once,
    543 	 * recording all forward links and backwards links too.  The parallel
    544 	 * "linkcount" data structure ensures that no room ends up with more
    545 	 * than three links, regardless of the quality of the random number
    546 	 * generator that we're using.
    547 	 */
    548 	srandom((int)time((time_t *)0));
    549 
    550 	/* initialize the cave first off. */
    551 	for (i = 1; i <= room_num; ++i)
    552 		for (j = 0; j < link_num ; ++j)
    553 			cave[i].tunnel[j] = -1;
    554 
    555 	/*
    556 	 * Choose a random 'hop' delta for our guaranteed link.
    557 	 * To keep the cave connected, we need the greatest common divisor
    558 	 * of (delta + 1) and room_num to be 1.
    559 	 */
    560 	do {
    561 		delta = (random() % (room_num - 1)) + 1;
    562 	} while (gcd(room_num, delta + 1) != 1);
    563 
    564 	for (i = 1; i <= room_num; ++i) {
    565 		link = ((i + delta) % room_num) + 1;	/* connection */
    566 		cave[i].tunnel[0] = link;		/* forw link */
    567 		cave[link].tunnel[1] = i;		/* back link */
    568 	}
    569 	/* now fill in the rest of the cave with random connections */
    570 	for (i = 1; i <= room_num; i++)
    571 		for (j = 2; j < link_num ; j++) {
    572 			if (cave[i].tunnel[j] != -1)
    573 				continue;
    574 try_again:		link = (random() % room_num) + 1;
    575 			/* skip duplicates */
    576 			for (k = 0; k < j; k++)
    577 				if (cave[i].tunnel[k] == link)
    578 					goto try_again;
    579 			cave[i].tunnel[j] = link;
    580 			if (random() % 2 == 1)
    581 				continue;
    582 			for (k = 0; k < link_num; ++k) {
    583 				/* if duplicate, skip it */
    584 				if (cave[link].tunnel[k] == i)
    585 					k = link_num;
    586 
    587 				/* if open link, use it, force exit */
    588 				if (cave[link].tunnel[k] == -1) {
    589 					cave[link].tunnel[k] = i;
    590 					k = link_num;
    591 				}
    592 			}
    593 		}
    594 	/*
    595 	 * now that we're done, sort the tunnels in each of the rooms to
    596 	 * make it easier on the intrepid adventurer.
    597 	 */
    598 	for (i = 1; i <= room_num; ++i)
    599 		qsort(cave[i].tunnel, (u_int)link_num,
    600 		    sizeof(cave[i].tunnel[0]), int_compare);
    601 
    602 #ifdef DEBUG
    603 	if (debug)
    604 		for (i = 1; i <= room_num; ++i) {
    605 			(void)printf("<room %d  has tunnels to ", i);
    606 			for (j = 0; j < link_num; ++j)
    607 				(void)printf("%d ", cave[i].tunnel[j]);
    608 			(void)printf(">\n");
    609 		}
    610 #endif
    611 }
    612 
    613 void
    614 clear_things_in_cave()
    615 {
    616 	int i;
    617 
    618 	/*
    619 	 * remove bats and pits from the current cave in preparation for us
    620 	 * adding new ones via the initialize_things_in_cave() routines.
    621 	 */
    622 	for (i = 1; i <= room_num; ++i)
    623 		cave[i].has_a_bat = cave[i].has_a_pit = 0;
    624 }
    625 
    626 void
    627 initialize_things_in_cave()
    628 {
    629 	int i, loc;
    630 
    631 	/* place some bats, pits, the wumpus, and the player. */
    632 	for (i = 0; i < bat_num; ++i) {
    633 		do {
    634 			loc = (random() % room_num) + 1;
    635 		} while (cave[loc].has_a_bat);
    636 		cave[loc].has_a_bat = 1;
    637 #ifdef DEBUG
    638 		if (debug)
    639 			(void)printf("<bat in room %d>\n", loc);
    640 #endif
    641 	}
    642 
    643 	for (i = 0; i < pit_num; ++i) {
    644 		do {
    645 			loc = (random() % room_num) + 1;
    646 		} while (cave[loc].has_a_pit && cave[loc].has_a_bat);
    647 		cave[loc].has_a_pit = 1;
    648 #ifdef DEBUG
    649 		if (debug)
    650 			(void)printf("<pit in room %d>\n", loc);
    651 #endif
    652 	}
    653 
    654 	wumpus_loc = (random() % room_num) + 1;
    655 #ifdef DEBUG
    656 	if (debug)
    657 		(void)printf("<wumpus in room %d>\n", loc);
    658 #endif
    659 
    660 	do {
    661 		player_loc = (random() % room_num) + 1;
    662 	} while (player_loc == wumpus_loc || (level == HARD ?
    663 	    (link_num / room_num < 0.4 ? wump_nearby() : 0) : 0));
    664 }
    665 
    666 int
    667 getans(prompt)
    668 	const char *prompt;
    669 {
    670 	char buf[20];
    671 
    672 	/*
    673 	 * simple routine to ask the yes/no question specified until the user
    674 	 * answers yes or no, then return 1 if they said 'yes' and 0 if they
    675 	 * answered 'no'.
    676 	 */
    677 	for (;;) {
    678 		(void)printf("%s", prompt);
    679 		(void)fflush(stdout);
    680 		if (!fgets(buf, sizeof(buf), stdin))
    681 			return(0);
    682 		if (*buf == 'N' || *buf == 'n')
    683 			return(0);
    684 		if (*buf == 'Y' || *buf == 'y')
    685 			return(1);
    686 		(void)printf(
    687 "I don't understand your answer; please enter 'y' or 'n'!\n");
    688 	}
    689 	/* NOTREACHED */
    690 }
    691 
    692 int
    693 bats_nearby()
    694 {
    695 	int i;
    696 
    697 	/* check for bats in the immediate vicinity */
    698 	for (i = 0; i < link_num; ++i)
    699 		if (cave[cave[player_loc].tunnel[i]].has_a_bat)
    700 			return(1);
    701 	return(0);
    702 }
    703 
    704 int
    705 pit_nearby()
    706 {
    707 	int i;
    708 
    709 	/* check for pits in the immediate vicinity */
    710 	for (i = 0; i < link_num; ++i)
    711 		if (cave[cave[player_loc].tunnel[i]].has_a_pit)
    712 			return(1);
    713 	return(0);
    714 }
    715 
    716 int
    717 wump_nearby()
    718 {
    719 	int i, j;
    720 
    721 	/* check for a wumpus within TWO caves of where we are */
    722 	for (i = 0; i < link_num; ++i) {
    723 		if (cave[player_loc].tunnel[i] == wumpus_loc)
    724 			return(1);
    725 		for (j = 0; j < link_num; ++j)
    726 			if (cave[cave[player_loc].tunnel[i]].tunnel[j] ==
    727 			    wumpus_loc)
    728 				return(1);
    729 	}
    730 	return(0);
    731 }
    732 
    733 void
    734 move_wump()
    735 {
    736 	wumpus_loc = cave[wumpus_loc].tunnel[random() % link_num];
    737 }
    738 
    739 int
    740 int_compare(a, b)
    741 	const void *a, *b;
    742 {
    743 	return(*(const int *)a < *(const int *)b ? -1 : 1);
    744 }
    745 
    746 void
    747 instructions()
    748 {
    749 	const char *pager;
    750 	pid_t pid;
    751 	int status;
    752 	int fd;
    753 
    754 	/*
    755 	 * read the instructions file, if needed, and show the user how to
    756 	 * play this game!
    757 	 */
    758 	if (!getans("Instructions? (y-n) "))
    759 		return;
    760 
    761 	if (access(_PATH_WUMPINFO, R_OK)) {
    762 		(void)printf(
    763 "Sorry, but the instruction file seems to have disappeared in a\n\
    764 puff of greasy black smoke! (poof)\n");
    765 		return;
    766 	}
    767 
    768 	if (!isatty(STDOUT_FILENO))
    769 		pager = "cat";
    770 	else {
    771 		if (!(pager = getenv("PAGER")) || (*pager == 0))
    772 			pager = _PATH_PAGER;
    773 	}
    774 	switch (pid = fork()) {
    775 	case 0: /* child */
    776 		if ((fd = open(_PATH_WUMPINFO, O_RDONLY)) == -1)
    777 			err(1, "open %s", _PATH_WUMPINFO);
    778 		if (dup2(fd, STDIN_FILENO) == -1)
    779 			err(1, "dup2");
    780 		(void)execl("/bin/sh", "sh", "-c", pager, (char *) NULL);
    781 		err(1, "exec sh -c %s", pager);
    782 	case -1:
    783 		err(1, "fork");
    784 	default:
    785 		(void)waitpid(pid, &status, 0);
    786 		break;
    787 	}
    788 }
    789 
    790 void
    791 usage()
    792 {
    793 	(void)fprintf(stderr,
    794 "usage: wump [-h] [-a arrows] [-b bats] [-p pits] [-r rooms] [-t tunnels]\n");
    795 	exit(1);
    796 }
    797 
    798 /* messages */
    799 
    800 void
    801 wump_kill()
    802 {
    803 	(void)printf(
    804 "*ROAR* *chomp* *snurfle* *chomp*!\n\
    805 Much to the delight of the Wumpus, you walked right into his mouth,\n\
    806 making you one of the easiest dinners he's ever had!  For you, however,\n\
    807 it's a rather unpleasant death.  The only good thing is that it's been\n\
    808 so long since the evil Wumpus cleaned his teeth that you immediately\n\
    809 passed out from the stench!\n");
    810 }
    811 
    812 void
    813 kill_wump()
    814 {
    815 	(void)printf(
    816 "*thwock!* *groan* *crash*\n\n\
    817 A horrible roar fills the cave, and you realize, with a smile, that you\n\
    818 have slain the evil Wumpus and won the game!  You don't want to tarry for\n\
    819 long, however, because not only is the Wumpus famous, but the stench of\n\
    820 dead Wumpus is also quite well known, a stench plenty enough to slay the\n\
    821 mightiest adventurer at a single whiff!!\n");
    822 }
    823 
    824 void
    825 no_arrows()
    826 {
    827 	(void)printf(
    828 "\nYou turn and look at your quiver, and realize with a sinking feeling\n\
    829 that you've just shot your last arrow (figuratively, too).  Sensing this\n\
    830 with its psychic powers, the evil Wumpus rampagees through the cave, finds\n\
    831 you, and with a mighty *ROAR* eats you alive!\n");
    832 }
    833 
    834 void
    835 shoot_self()
    836 {
    837 	(void)printf(
    838 "\n*Thwack!*  A sudden piercing feeling informs you that the ricochet\n\
    839 of your wild arrow has resulted in it wedging in your side, causing\n\
    840 extreme agony.  The evil Wumpus, with its psychic powers, realizes this\n\
    841 and immediately rushes to your side, not to help, alas, but to EAT YOU!\n\
    842 (*CHOMP*)\n");
    843 }
    844 
    845 void
    846 jump(where)
    847 	int where;
    848 {
    849 	(void)printf(
    850 "\nWith a jaunty step you enter the magic tunnel.  As you do, you\n\
    851 notice that the walls are shimmering and glowing.  Suddenly you feel\n\
    852 a very curious, warm sensation and find yourself in room %d!!\n", where);
    853 }
    854 
    855 void
    856 pit_kill()
    857 {
    858 	(void)printf(
    859 "*AAAUUUUGGGGGHHHHHhhhhhhhhhh...*\n\
    860 The whistling sound and updraft as you walked into this room of the\n\
    861 cave apparently wasn't enough to clue you in to the presence of the\n\
    862 bottomless pit.  You have a lot of time to reflect on this error as\n\
    863 you fall many miles to the core of the earth.  Look on the bright side;\n\
    864 you can at least find out if Jules Verne was right...\n");
    865 }
    866 
    867 void
    868 pit_survive()
    869 {
    870 	(void)printf(
    871 "Without conscious thought you grab for the side of the cave and manage\n\
    872 to grasp onto a rocky outcrop.  Beneath your feet stretches the limitless\n\
    873 depths of a bottomless pit!  Rock crumbles beneath your feet!\n");
    874 }
    875