Mega Code Archive
Basic double linked list fragment
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#include <stdio.h>
#include <stdlib.h>
struct dllist {
int number;
struct dllist *next;
struct dllist *prev;
};
struct dllist *head, *tail;
void append_node(struct dllist *lnode);
void insert_node(struct dllist *lnode, struct dllist *after);
void remove_node(struct dllist *lnode);
int main(void) {
struct dllist *lnode;
int i = 0;
/* add some numbers to the double linked list */
for(i = 0; i <= 5; i++) {
lnode = (struct dllist *)malloc(sizeof(struct dllist));
lnode->number = i;
append_node(lnode);
}
/* print the dll list */
for(lnode = head; lnode != NULL; lnode = lnode->next) {
printf("%d\n", lnode->number);
}
/* destroy the dll list */
while(head != NULL)
remove_node(head);
return 0;
}
void append_node(struct dllist *lnode) {
if(head == NULL) {
head = lnode;
lnode->prev = NULL;
} else {
tail->next = lnode;
lnode->prev = tail;
}
tail = lnode;
lnode->next = NULL;
}
void insert_node(struct dllist *lnode, struct dllist *after) {
lnode->next = after->next;
lnode->prev = after;
if(after->next != NULL)
after->next->prev = lnode;
else
tail = lnode;
after->next = lnode;
}
void remove_node(struct dllist *lnode) {
if(lnode->prev == NULL)
head = lnode->next;
else
lnode->prev->next = lnode->next;
if(lnode->next == NULL)
tail = lnode->prev;
else
lnode->next->prev = lnode->prev;
}
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