Page 174 - ARM 64 Bit Assembly Language

Abstract data types 161

26 { wordlist* tmp;
27 tmp = (wordlist*)malloc(sizeof(wordlist));
28 if(tmp == NULL)
29 {
30 printf("Unable to allocate wordlist\n");
31 exit(1);
32 }
33 tmp->nwords = 0;
34 tmp->head = NULL;
35 return tmp;
36 }
37
38 /**********************************************************/
39 /* wl_free frees all the storage used by a wordlist */
40 void wl_free(wordlist* wl)
41 {
42 wordlistnode *tmpa, *tmpb;
43 tmpa = wl->head;
44 while(tmpa != NULL)
45 {
46 tmpb = tmpa;
47 tmpa = tmpa->next;
48 free(tmpb->word);
49 free(tmpb);
50 }
51 free(wl);
52 }
53
54 /*********************************************************/
55 /* wln_lookup is used internally to search the list of */
56 /* words. It returns a pointer to the wordlistnode. If */
57 /* the word is not in the list, then it returns a pointer*/
58 /* to the place where the word should be inserted. If */
59 /* the insertion point is the head of the list, then it */
60 /* returns NULL. */
61 wordlistnode* wln_lookup(wordlistnode* lst, char *word)
62 {
63 wordlistnode *prev = NULL;
64 while((lst != NULL)&&(strcmp(lst->word, word)<0))
65 {
66 prev = lst;
67 lst = lst->next;
68 }
69 if((lst != NULL)&&(strcmp(lst->word, word) == 0))
70 return lst;
71 else
72 return prev;
73 }
74