doubly_linked.c

#include <stdio.h>
#include <stdlib.h>

// 定义节点结构体
struct Node {
    int data;
    struct Node* next;
    struct Node* prev;
};

// 打印链表
void printList(struct Node* head) {
    struct Node* temp = head;
    while (temp != NULL) {
        printf("%d <-> ", temp->data);
        temp = temp->next;
    }
    printf("NULL\n");
}

// 插入节点到尾部
void appendNode(struct Node** head, int data) {
    struct Node* newNode = (struct Node*) malloc(sizeof(struct Node));
    struct Node* last = *head;
    
    newNode->data = data;
    newNode->next = NULL;
    newNode->prev = NULL;
    
    if (*head == NULL) {
        *head = newNode;
        return;
    }
    
    while (last->next != NULL) {
        last = last->next;
    }
    last->next = newNode;
    newNode->prev = last;
}

int main() {
    struct Node* head = NULL;

    // 插入节点
    appendNode(&head, 1);
    appendNode(&head, 2);
    appendNode(&head, 3);

    printList(head);  // 输出：1 <-> 2 <-> 3 <-> NULL
    return 0;
}

/*
jarry@MacBook-Pro linked % gcc doubly_linked.c
jarry@MacBook-Pro linked % ./a.out 
1 <-> 2 <-> 3 <-> NULL
*/