manual/examples/search.c

   1 #include <stdlib.h>
   2 #include <stdio.h>
   3 #include <string.h>
   4
   5 /* Define an array of critters to sort. */
   6
   7 struct critter
   8   {
   9     const char *name;
  10     const char *species;
  11   };
  12
  13 struct critter muppets[] =
  14   {
  15     {"Kermit", "frog"},
  16     {"Piggy", "pig"},
  17     {"Gonzo", "whatever"},
  18     {"Fozzie", "bear"},
  19     {"Sam", "eagle"},
  20     {"Robin", "frog"},
  21     {"Animal", "animal"},
  22     {"Camilla", "chicken"},
  23     {"Sweetums", "monster"},
  24     {"Dr. Strangepork", "pig"},
  25     {"Link Hogthrob", "pig"},
  26     {"Zoot", "human"},
  27     {"Dr. Bunsen Honeydew", "human"},
  28     {"Beaker", "human"},
  29     {"Swedish Chef", "human"}
  30   };
  31
  32 int count = sizeof (muppets) / sizeof (struct critter);
  33
  34
  35
  36 /* This is the comparison function used for sorting and searching. */
  37
  38 int
  39 critter_cmp (const struct critter *c1, const struct critter *c2)
  40 {
  41   return strcmp (c1->name, c2->name);
  42 }
  43
  44
  45 /* Print information about a critter. */
  46
  47 void
  48 print_critter (const struct critter *c)
  49 {
  50   printf ("%s, the %s\n", c->name, c->species);
  51 }
  52
  53
  54 /*@group*/
  55 /* Do the lookup into the sorted array. */
  56
  57 void
  58 find_critter (const char *name)
  59 {
  60   struct critter target, *result;
  61   target.name = name;
  62   result = bsearch (&target, muppets, count, sizeof (struct critter),
  63                     critter_cmp);
  64   if (result)
  65     print_critter (result);
  66   else
  67     printf ("Couldn't find %s.\n", name);
  68 }
  69 /*@end group*/
  70
  71 /* Main program. */
  72
  73 int
  74 main (void)
  75 {
  76   int i;
  77
  78   for (i = 0; i < count; i++)
  79     print_critter (&muppets[i]);
  80   printf ("\n");
  81
  82   qsort (muppets, count, sizeof (struct critter), critter_cmp);
  83
  84   for (i = 0; i < count; i++)
  85     print_critter (&muppets[i]);
  86   printf ("\n");
  87
  88   find_critter ("Kermit");
  89   find_critter ("Gonzo");
  90   find_critter ("Janice");
  91
  92   return 0;
  93 }