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This article is a detailed introduction to "C language how to achieve two-way linked list and two-way circular linked list", detailed content, clear steps, details properly handled, I hope this article "C language how to achieve two-way linked list and two-way circular linked list" article can help you solve doubts, the following follow the small series of ideas slowly in-depth, together to learn new knowledge bar.

Double-linked lists and double-linked circular lists

Compared with the one-way linked list, there is one more precursor node. If it is empty, then next and prior both point to themselves. For double-loop lists, you only need the next of the last element to point to head->next, and the prior of head->next to point to the last node.

insert operation

The new node s is inserted into the list, s->next to node p, s->prior to p->prior, then p->prior->next points to s, p->prior points to s. Order needs attention

s->next = p;s->prior = p->prior;p->prior->next = s;p->prior = s;

delete operation

Remove node p. p->next->prior points to p->prior, p->prior->next points to p->next. Finally, delete the p node.

p->prior->next = p->next;p->next->prior = p->prior;delete p;

example operation

(Screenshot attached)

Note: Because the function does not return a Node* type, the pointer is referenced here, otherwise the change is not saved when exiting the function. If you need to delete all linked lists, you need to save the head address after InitList, otherwise you will miss a Node node that has not been deleted.

Code implementation:

#include#include #includeusing namespace std;const int OK = 1;const int ERROR = 0;const int LETTERNUM = 26;typedef char ElemType;struct Node{ ElemType data; Node * prior;//front drive node Node * next;//rear drive node};int InitList(Node *&L){ Node *p,*q; int i; L = new Node; //head node L->next = L->prior = NULL; p = L; //p is the current pointer for(int i=0;idata = 'A' + i; q->prior = p; q->next = p->next; p->next = q; p = q;//pointer movement } p->next = L->next; //tail node points to head->next(first letter address) L->next->prior = p; return OK;}void Change(Node *&L,int i){ //Move head pointer if (i>0){ while(i--){ L = L->next; } } else if (inext ; while(i++){ L = L->prior; } } else{ L = L->next; }}int main(){ Node *head = NULL; int i,n; InitList(head); //Node *s_head = head; cout

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