1  /* Searching and Sorting Example
       2     Copyright (C) 1991-2023 Free Software Foundation, Inc.
       3  
       4     This program is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU General Public License
       6     as published by the Free Software Foundation; either version 2
       7     of the License, or (at your option) any later version.
       8  
       9     This program is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12     GNU General Public License for more details.
      13  
      14     You should have received a copy of the GNU General Public License
      15     along with this program; if not, see <https://www.gnu.org/licenses/>.
      16  */
      17  
      18  #include <stdlib.h>
      19  #include <stdio.h>
      20  #include <string.h>
      21  
      22  /* Define an array of critters to sort. */
      23  
      24  struct critter
      25    {
      26      const char *name;
      27      const char *species;
      28    };
      29  
      30  struct critter muppets[] =
      31    {
      32      {"Kermit", "frog"},
      33      {"Piggy", "pig"},
      34      {"Gonzo", "whatever"},
      35      {"Fozzie", "bear"},
      36      {"Sam", "eagle"},
      37      {"Robin", "frog"},
      38      {"Animal", "animal"},
      39      {"Camilla", "chicken"},
      40      {"Sweetums", "monster"},
      41      {"Dr. Strangepork", "pig"},
      42      {"Link Hogthrob", "pig"},
      43      {"Zoot", "human"},
      44      {"Dr. Bunsen Honeydew", "human"},
      45      {"Beaker", "human"},
      46      {"Swedish Chef", "human"}
      47    };
      48  
      49  int count = sizeof (muppets) / sizeof (struct critter);
      50  
      51  
      52  
      53  /* This is the comparison function used for sorting and searching. */
      54  
      55  int
      56  critter_cmp (const void *v1, const void *v2)
      57  {
      58    const struct critter *c1 = v1;
      59    const struct critter *c2 = v2;
      60  
      61    return strcmp (c1->name, c2->name);
      62  }
      63  
      64  
      65  /* Print information about a critter. */
      66  
      67  void
      68  print_critter (const struct critter *c)
      69  {
      70    printf ("%s, the %s\n", c->name, c->species);
      71  }
      72  
      73  
      74  /*@group*/
      75  /* Do the lookup into the sorted array. */
      76  
      77  void
      78  find_critter (const char *name)
      79  {
      80    struct critter target, *result;
      81    target.name = name;
      82    result = bsearch (&target, muppets, count, sizeof (struct critter),
      83  		    critter_cmp);
      84    if (result)
      85      print_critter (result);
      86    else
      87      printf ("Couldn't find %s.\n", name);
      88  }
      89  /*@end group*/
      90  
      91  /* Main program. */
      92  
      93  int
      94  main (void)
      95  {
      96    int i;
      97  
      98    for (i = 0; i < count; i++)
      99      print_critter (&muppets[i]);
     100    printf ("\n");
     101  
     102    qsort (muppets, count, sizeof (struct critter), critter_cmp);
     103  
     104    for (i = 0; i < count; i++)
     105      print_critter (&muppets[i]);
     106    printf ("\n");
     107  
     108    find_critter ("Kermit");
     109    find_critter ("Gonzo");
     110    find_critter ("Janice");
     111  
     112    return 0;
     113  }