glibc/manual/examples/search.c

114 lines
2.5 KiB
C

/* Searching and Sorting Example
Copyright (C) 1991-2017 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, if not, see <http://www.gnu.org/licenses/>.
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
/* Define an array of critters to sort. */
struct critter
{
const char *name;
const char *species;
};
struct critter muppets[] =
{
{"Kermit", "frog"},
{"Piggy", "pig"},
{"Gonzo", "whatever"},
{"Fozzie", "bear"},
{"Sam", "eagle"},
{"Robin", "frog"},
{"Animal", "animal"},
{"Camilla", "chicken"},
{"Sweetums", "monster"},
{"Dr. Strangepork", "pig"},
{"Link Hogthrob", "pig"},
{"Zoot", "human"},
{"Dr. Bunsen Honeydew", "human"},
{"Beaker", "human"},
{"Swedish Chef", "human"}
};
int count = sizeof (muppets) / sizeof (struct critter);
/* This is the comparison function used for sorting and searching. */
int
critter_cmp (const void *v1, const void *v2)
{
const struct critter *c1 = v1;
const struct critter *c2 = v2;
return strcmp (c1->name, c2->name);
}
/* Print information about a critter. */
void
print_critter (const struct critter *c)
{
printf ("%s, the %s\n", c->name, c->species);
}
/*@group*/
/* Do the lookup into the sorted array. */
void
find_critter (const char *name)
{
struct critter target, *result;
target.name = name;
result = bsearch (&target, muppets, count, sizeof (struct critter),
critter_cmp);
if (result)
print_critter (result);
else
printf ("Couldn't find %s.\n", name);
}
/*@end group*/
/* Main program. */
int
main (void)
{
int i;
for (i = 0; i < count; i++)
print_critter (&muppets[i]);
printf ("\n");
qsort (muppets, count, sizeof (struct critter), critter_cmp);
for (i = 0; i < count; i++)
print_critter (&muppets[i]);
printf ("\n");
find_critter ("Kermit");
find_critter ("Gonzo");
find_critter ("Janice");
return 0;
}