genstructs/linkedlist.c

   1 /* compile with:
   2    gcc linkedlist.c -o linkedlist -Wall -W -Wextra -ansi -pedantic */
   3
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <sys/queue.h>
   8
   9 LIST_HEAD(listhead, entry) head;
  10 struct listhead *headp;
  11
  12 struct entry {
  13     LIST_ENTRY(entry) entries;
  14     const char *str;
  15 } *np, *n;
  16
  17 int main(void)
  18 {
  19     const char *str[] = { "this", "is", "a", "linked", "list" };
  20     unsigned int i;
  21
  22     /* Initialize list */
  23     LIST_INIT(&head);
  24     headp = &head;
  25
  26     /* Populate list with str[] items */
  27     for (i = 0; i < sizeof str / sizeof *str; i++) {
  28         if ((n = malloc(sizeof(struct entry))) == NULL) {
  29             perror("malloc");
  30             goto CLEANUP_AND_EXIT;
  31         }
  32         n->str = str[i];
  33
  34         if (i == 0)
  35             LIST_INSERT_HEAD(&head, n, entries);
  36         else
  37             LIST_INSERT_AFTER(np, n, entries);
  38         np = n;
  39     }
  40
  41     /* Traverse list */
  42     LIST_FOREACH(np, &head, entries)
  43         printf("%s\n", np->str);
  44
  45  CLEANUP_AND_EXIT:;
  46     /* Delete all elements */
  47     while (LIST_FIRST(&head) != NULL)
  48         LIST_REMOVE(LIST_FIRST(&head), entries);
  49
  50     return EXIT_SUCCESS;
  51 }