[Data structure] doubly linked list

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1. typedef struct node{
2. struct NODE *fwd;
3. struct NODE *bwd;
4. int value;
5. }node;

The bwd pointer of the root node of the doubly linked list points to the last node of the doubly linked list, the FWD pointer to the first node of the doubly linked list, and the value field of the doubly linked list as null

The following program inserts a value into an ordered double-linked list, and if a node already has the same value in the linked list, it is not inserted

[CPP]View Plaincopy

2. #include <stdio.h>
4. #include <stdlib.h>
8. typedef struct node{
10. struct NODE *bwd;
12. struct NODE *fwd;
14. int value;
16. }node;
20. BOOL Insert (Node *rootnode,int newvalue);
24. BOOL Insert (Node *rootnode,int newvalue)
26. {
28. Node Temnode;
30. int i = 0;
32. Temnode = Rootnode;
34. Node *newnode = (node*) malloc (sizeof (Node));
36. if (newnode ==null)
38. {
40. printf ("malloc fail");
42. return false;
44. }
46. Newnode->value = newvalue;
48. if (rootnode->bwd = = NULL)
50. {
52. ROOTNODE->BWD = NewNode;
54. ROOTNODE->FWD = NewNode;
56. return true;
58. }
60. For (; TEMNODE->FWD! = Null;temnode = temnode->fwd)
62. {
64. i++;
66. if (Temnode->value = = newvalue)
68. {
70. printf ("NewValue is already in double link list");
72. return true;
74. }
76. if (Temnode->value > NewValue)
78. {
80. if (i==1)
82. {
84. NEWNODE->FWD = rootnode->fwd;
86. ROOTNODE->FWD = NewNode;
88. NEWNODE->BWD = Rootnode;
90. newnode->fwd->bwd=newnode;
92. }
94. Else
96. {
98. Temnode = temnode->bwd;
100. NEWNODE->FWD = temnode->fwd;
102. TEMNODE->FWD = NewNode;
104. NEWNODE->BWD = Temnode;
106. newnode->fwd->bwd=newnode;
108. }
110. }
112. Else
114. {
116. Temnode = temnode->bwd;
118. NewNode = temnode->fwd;
120. NEWNODE->BWD = Temnode;
122. }
124. }
128. return true;
132. }

[Data structure] doubly linked list