/* Using qsort() and bsearch() with strings. */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX 20

int comp(const void *s1, const void *s2);

main()
{
     char *data[MAX], buf[80], *ptr, *key, **key1;
     int count;

     /* Input a list of words. */

     printf("Enter %d words, pressing Enter after each.\n", MAX);

     for (count = 0; count < MAX; count++)
     {
         printf("Word %d: ", count+1);
         gets(buf);
         data[count] = malloc(strlen(buf)+1);
         strcpy(data[count], buf);
     }

     /* Sort the words (actually, sort the pointers). */

     qsort(data, MAX, sizeof(data[0]), comp);

     /* Display the sorted words. */

     for (count = 0; count < MAX; count++)
         printf("\n%d: %s", count+1, data[count]);

     /* Get a search key. */

     printf("\n\nEnter a search key: ");
     gets(buf);

     /* Perform the search. First, make key1 a pointer */
     /* to the pointer to the search key.*/

     key = buf;
     key1 = &key;
     ptr = bsearch(key1, data, MAX, sizeof(data[0]), comp);

     if (ptr != NULL)
         printf("%s found.", buf);
     else
         printf("%s not found", buf);
     return(0);
}

int comp(const void *s1, const void *s2)
{
     return (strcmp(*(char **)s1, *(char **)s2));
}