c++双向链表相关函数及其代码

双向链表是一种常见的数据结构，它比单向链表更加灵活，因为它可以从前向后遍历，也可以从后向前遍历。下面是双向链表的相关函数及其代码实现。

1. 创建双向链表

typedef struct Node{
    int data;
    struct Node *prev;
    struct Node *next;
}Node, *List;

List createList(){
    List head = (List)malloc(sizeof(Node));
    head->prev = NULL;
    head->next = NULL;
    return head;
}

2. 在双向链表中插入节点

void insert(List head, int data, int position){
    Node *p = head;
    Node *newNode = (Node*)malloc(sizeof(Node));
    newNode->data = data;
    newNode->prev = NULL;
    newNode->next = NULL;
    int i = 0;
    while(p->next && i < position){
        p = p->next;
        i++;
    }
    if(i != position){
        printf("Position is not valid!\n");
        return;
    }
    newNode->prev = p;
    newNode->next = p->next;
    if(p->next){
        p->next->prev = newNode;
    }
    p->next = newNode;
}

3. 删除双向链表中的节点

void delete(List head, int position){
    Node *p = head;
    int i = 0;
    while(p->next && i < position){
        p = p->next;
        i++;
    }
    if(i != position){
        printf("Position is not valid!\n");
        return;
    }
    p->prev->next = p->next;
    if(p->next){
        p->next->prev = p->prev;
    }
    free(p);
}

4. 修改双向链表中的节点

void update(List head, int position, int data){
    Node *p = head;
    int i = 0;
    while(p->next && i < position){
        p = p->next;
        i++;
    }
    if(i != position){
        printf("Position is not valid!\n");
        return;
    }
    p->data = data;
}

5. 查找双向链表中的节点

Node* search(List head, int data){
    Node *p = head->next;
    while(p){
        if(p->data == data){
            return p;
        }
        p = p->next;
    }
    return NULL;
}

6. 遍历双向链表

void traverse(List head){
    Node *p = head->next;
    while(p){
        printf("%d ", p->data);
        p = p->next;
    }
    printf("\n");
}

以上就是双向链表的相关函数及其代码实现。