1 #include<stdio.h>
2 #include<stdlib.h>
3
4 typedef struct node{
5 int val;
6 struct node *prev, *next;
7 }node;
8
9 node *head = NULL;
10
11 node* insert_after(node *n, int val){
12 // insert_after next to current node
13 node *newnode = (node*)malloc(sizeof(node));
14 newnode->val = val;
15 newnode->next = NULL;
16 newnode->prev = NULL;
17 if(n == NULL){
18 n = newnode;
19 }else{
20 newnode->next = n->next;
21 newnode->prev = n;
22
23 if(n->next != NULL) n->next->prev = newnode;
24 n->next = newnode;
25 }
26 return n;
27 }
28
29 node* insert_before(node *n, int val){
30 if(n == NULL){
31 n = insert_after(n, val);
32 }else{
33 node *prev = n->prev;
34 if(prev == NULL){
35 // insert at head return new head
36 prev = insert_after(prev, val);
37 prev->next = n;
38 n->prev = prev;
39 n = prev;
40 }else{
41 prev = insert_after(prev, val);
42 }
43
44 }
45 return n;
46 }
47
48 node* remove(node *n){
49 node *removenode = n;
50 node *returnnode = NULL;
51 if(n->prev != NULL){
52 n->prev->next = n->next;
53 returnnode = n->prev;
54 }
55 if(n->next != NULL){
56 n->next->prev = n->prev;
57 returnnode = n->next;
58 }
59 free(removenode);
60 return returnnode;
61 }
62
63 void print_list(node *head){
64 printf("List : ");
65 if(head == NULL){
66 printf("--EMPTY--");
67 }
68 while(head != NULL){
69 printf("%d ", head->val);
70 head = head->next;
71 }
72
73 printf("\n");
74 }
75
76 int main(){
77 head = insert_after(head, 1);
78 print_list(head);
79 head = insert_after(head, 2);
80 print_list(head);
81 head = insert_after(head, 3);
82 print_list(head);
83 head = insert_before(head, 4);
84 print_list(head);
85 head = insert_before(head, 5);
86 print_list(head);
87
88 node *temp = head->next->next;
89 temp = insert_after(temp, 6);
90 print_list(head);
91
92 head = remove(head);
93 print_list(head);
94 head = remove(head);
95 print_list(head);
96 head = remove(head);
97 print_list(head);
98
99 temp = head->next;
100 temp = remove(temp);
101 print_list(head);
102
103 temp = head->next;
104 temp = remove(temp);
105 print_list(head);
106
107
108 head = remove(head);
109 print_list(head);
110 }
1 #include<stdio.h>
2 #include<stdlib.h>
3
4 struct Node {
5 int val;
6 Node* next;
7 };
8
9 Node* new_node(int val) {
10 Node* node = (Node*)malloc(sizeof(Node));
11 node->val = val;
12 node->next = NULL;
13 return node;
14 }
15
16 // ถ้าไม่เจอจะ return โหนดสุดท้าย
17 Node* find_parent(Node* node, int val) {
18 if(node == NULL)return NULL;
19 if(node->next == NULL)return node;
20 if(node->next->val == val)return node;
21 return find_parent(node->next, val);
22 }
23
24 Node* find(Node* node, int val) {
25 if(node == NULL)return NULL;
26 if(node->val == val)return node;
27 return find(node->next, val);
28 }
29
30 void insert(Node* root, int val) {
31 Node* node = new_node(val);
32 node->next = root->next;
33 root->next = node;
34 }
35
36 void insert_before(Node* root, int p_val, int val) {
37 Node* parent = find_parent(root, p_val);
38 if(parent == NULL)return;
39 insert(parent, val);
40 }
41
42 void delete_node(Node* node, int val) {
43 Node* parent = find_parent(node, val);
44 if(parent == NULL)return;
45 if(parent->next == NULL)return;
46 Node* tmp = parent->next;
47 parent->next = parent->next->next;
48 free(tmp);
49 }
50
51 void print_recursive(Node* node) {
52 if(node == NULL)return;
53 printf("%d ", node->val);
54 print_recursive(node->next);
55 }
56
57 void print_for(Node* node) {
58 for( ; node != NULL; node = node->next)
59 printf("%d ", node->val);
60 }
61
62 int main(int argc, char *argv[])
63 {
64 Node* root = new_node(0);
65
66 for(int i = 1; i <= 10; i++) {
67 insert(root, i);
68 print_recursive(root->next);
69 printf("\n");
70 }
71 printf("\n");
72
73 for(int i = 1; i <= 10; i += 4) {
74 delete_node(root, i);
75 print_for(root->next);
76 printf("\n");
77 }
78 printf("\n");
79
80 for(int i = 1; i <= 10; i += 3) {
81 insert_before(root, i, i * 2);
82 print_for(root->next);
83 printf("\n");
84 }
85 printf("\n");
86
87 getchar();
88
89 return 0;
90 }
