152 lines
2.9 KiB
C
152 lines
2.9 KiB
C
#include <stdio.h>
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#include <malloc.h>
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#include <limits.h>
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struct Node {
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struct Node *next;
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struct Node *prev;
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void *dta;
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};
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typedef struct Node Node;
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typedef struct {
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Node *head;
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unsigned length;
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} List;
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List *newList() {
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List *list = malloc(sizeof(List));
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return list;
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}
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Node *_newNode(Node *next, Node *prev, void *dta) {
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Node *newnode = malloc(sizeof(Node));
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newnode->next = next;
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newnode->prev = prev;
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newnode->dta = dta;
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return newnode;
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}
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Node *_traverseToLast(Node *node) {
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if (node->next != NULL) {
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return _traverseToLast(node->next);
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} else {
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return node;
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}
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}
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Node *_traverseToPos(Node *node, int pos) {
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if (pos > 0) {
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if (node->next != NULL) {
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return _traverseToPos(node->next, pos - 1);
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} else {
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return NULL;
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}
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} else {
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return node;
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}
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}
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void append(List *list, void *elem) {
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if (list->head == NULL) {
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// create head
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list->head = _newNode(NULL, NULL, elem);
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} else {
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// append element
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Node *last = _traverseToLast(list->head);
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last->next = _newNode(NULL, last, elem);
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}
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}
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int _length(Node *node) {
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if (node->next == NULL) {
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return 1;
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} else {
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return 1 + _length(node->next);
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}
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}
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int length(List *list) {
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if (list->head == NULL) {
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return 0;
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}
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return _length(list->head);
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}
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void insert(List *list, int position) {
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}
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void delete(List *list, int position) {
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Node *todel = _traverseToPos(list->head, position);
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if (todel->prev == NULL) {
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// we are the header
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list->head = todel->next;
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if (list->head != NULL) {
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list->head->prev = NULL;
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}
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} else if (todel->next == NULL) {
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// we are the last item
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todel->prev->next = NULL;
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} else {
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todel->prev->next = todel->next;
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todel->next->prev = todel->prev;
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}
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free(todel);
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}
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void deleteAll(List *list) {
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while (list->head != NULL) {
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delete(list, 0);
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}
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}
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void deleteList(List *list) {
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deleteAll(list);
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free(list);
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}
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List *merge(List *list1, List *list2) {
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return NULL;
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}
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void *first(List *list) {
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return list->head->dta;
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}
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void *last(List *list) {
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return _traverseToLast(list->head)->dta;
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}
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void print(List *list, char *typeFormatter) {
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Node *curr = list->head;
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while (curr != NULL) {
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printf(typeFormatter, curr->dta);
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printf("\n");
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curr = curr->next;
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}
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}
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int main() {
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printf("Hello, World!\n");
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List *mylist = newList();
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append(mylist, "test");
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append(mylist, "test2");
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append(mylist, "test3");
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print(mylist, "%s");
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printf("length is: %d\n", length(mylist));
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printf("\n");
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deleteAll(mylist);
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printf("length is: %d\n", length(mylist));
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print(mylist, "%s");
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deleteList(mylist);
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return 0;
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}
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