c语言双向链表怎么建立
要建立一个双向链表,需要定义一个包含两个指针(指向前一个节点和后一个节点)和数据的结构体。然后按照以下步骤进行建立:
- 定义一个结构体表示链表的节点:
struct Node { int data; struct Node* prev; struct Node* next; };
- 定义一个指向链表头部和尾部的指针:
struct Node* head = NULL; struct Node* tail = NULL;
- 创建一个新节点并赋值:
struct Node* newNode = (struct Node*)malloc(sizeof(struct Node)); newNode->data = value; newNode->prev = NULL; newNode->next = NULL;
- 如果链表为空,则将新节点设为头部和尾部:
if (head == NULL) { head = newNode; tail = newNode; }
- 如果链表不为空,则将新节点添加到尾部:
注意更新新节点和尾部节点的指针。else { tail->next = newNode; newNode->prev = tail; tail = newNode; }
- 重复步骤3-5,直到完成所有节点的添加。
完整的示例代码如下:
#include <stdio.h>
#include <stdlib.h>
struct Node {
int data;
struct Node* prev;
struct Node* next;
};
void insert(int value) {
struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
newNode->data = value;
newNode->prev = NULL;
newNode->next = NULL;
if (head == NULL) {
head = newNode;
tail = newNode;
}
else {
tail->next = newNode;
newNode->prev = tail;
tail = newNode;
}
}
void display() {
struct Node* current = head;
if (head == NULL) {
printf("List is empty.\n");
return;
}
printf("Nodes in the doubly linked list: \n");
while (current != NULL) {
printf("%d ", current->data);
current = current->next;
}
printf("\n");
}
int main() {
head = NULL;
tail = NULL;
insert(1);
insert(2);
insert(3);
display();
return 0;
}
这个示例代码创建了一个包含三个节点(1,2,3)的双向链表,并打印出节点的值。输出结果为:Nodes in the doubly linked list: 1 2 3