📅 最后修改于: 2023-12-03 14:40:25.059000 🧑 作者: Mango
这是一个基于C语言的双向链表操作的菜单驱动程序，具有插入、删除、查找、打印等基本操作。
双向链表是常用的一种数据结构，它由多个节点组成，每个节点包含一个数据域和两个指针域，指向前一个节点和后一个节点。相比于单向链表，双向链表可以实现更灵活的操作。
本程序实现了基本的双向链表操作，包括：
以下是本程序的核心代码片段，详细的注释可以帮助理解每个函数的功能。
//节点结构体
typedef struct Node {
int data;
struct Node* prev;
struct Node* next;
} Node;
//在头部插入节点
Node* insertAtHead(Node* head, int data) {
Node* newNode = (Node*)malloc(sizeof(Node));
newNode->data = data;
newNode->prev = NULL;
newNode->next = head;
if (head != NULL) {
head->prev = newNode;
}
head = newNode;
return head;
}
//在尾部插入节点
Node* insertAtTail(Node* head, int data) {
Node* newNode = (Node*)malloc(sizeof(Node));
newNode->data = data;
newNode->prev = NULL;
newNode->next = NULL;
if (head == NULL) {
head = newNode;
} else {
Node* current = head;
while (current->next != NULL) {
current = current->next;
}
current->next = newNode;
newNode->prev = current;
}
return head;
}
//在指定位置插入节点
Node* insertAtPosition(Node* head, int data, int position) {
Node* newNode = (Node*)malloc(sizeof(Node));
newNode->data = data;
newNode->prev = NULL;
newNode->next = NULL;
if (position == 1) { //在头部插入
head = insertAtHead(head, data);
} else {
Node* current = head;
int i;
for (i = 1; i < position-1 && current != NULL; i++) {
current = current->next;
}
if (current != NULL) {
newNode->prev = current;
newNode->next = current->next;
if (current->next != NULL) {
current->next->prev = newNode;
}
current->next = newNode;
} else {
printf("Error: invalid position.\n");
}
}
return head;
}
//删除指定位置节点
Node* deleteAtPosition(Node* head, int position) {
if (head == NULL) {
printf("Error: empty list.\n");
return head;
}
if (position == 1) { //删除头部节点
Node* current = head->next;
free(head);
head = current;
if (head != NULL) {
head->prev = NULL;
}
} else {
Node* current = head;
int i;
for (i = 1; i < position && current != NULL; i++) {
current = current->next;
}
if (current != NULL) {
if (current->prev != NULL) {
current->prev->next = current->next;
}
if (current->next != NULL) {
current->next->prev = current->prev;
}
free(current);
} else {
printf("Error: invalid position.\n");
}
}
return head;
}
//查找指定节点
Node* search(Node* head, int key) {
Node* current = head;
while (current != NULL) {
if (current->data == key) {
printf("Node with data %d found.\n", key);
return current;
}
current = current->next;
}
printf("Node with data %d not found.\n", key);
return NULL;
}
//打印所有节点
void printList(Node* head) {
Node* current = head;
printf("List: ");
while (current != NULL) {
printf("%d ", current->data);
current = current->next;
}
printf("\n");
}
以下是本程序的使用示例，可以根据需要进行修改并编译运行。
#include <stdio.h>
#include <stdlib.h>
//节点结构体
typedef struct Node {
int data;
struct Node* prev;
struct Node* next;
} Node;
//在头部插入节点
Node* insertAtHead(Node* head, int data) {
Node* newNode = (Node*)malloc(sizeof(Node));
newNode->data = data;
newNode->prev = NULL;
newNode->next = head;
if (head != NULL) {
head->prev = newNode;
}
head = newNode;
return head;
}
//在尾部插入节点
Node* insertAtTail(Node* head, int data) {
Node* newNode = (Node*)malloc(sizeof(Node));
newNode->data = data;
newNode->prev = NULL;
newNode->next = NULL;
if (head == NULL) {
head = newNode;
} else {
Node* current = head;
while (current->next != NULL) {
current = current->next;
}
current->next = newNode;
newNode->prev = current;
}
return head;
}
//在指定位置插入节点
Node* insertAtPosition(Node* head, int data, int position) {
Node* newNode = (Node*)malloc(sizeof(Node));
newNode->data = data;
newNode->prev = NULL;
newNode->next = NULL;
if (position == 1) { //在头部插入
head = insertAtHead(head, data);
} else {
Node* current = head;
int i;
for (i = 1; i < position-1 && current != NULL; i++) {
current = current->next;
}
if (current != NULL) {
newNode->prev = current;
newNode->next = current->next;
if (current->next != NULL) {
current->next->prev = newNode;
}
current->next = newNode;
} else {
printf("Error: invalid position.\n");
}
}
return head;
}
//删除指定位置节点
Node* deleteAtPosition(Node* head, int position) {
if (head == NULL) {
printf("Error: empty list.\n");
return head;
}
if (position == 1) { //删除头部节点
Node* current = head->next;
free(head);
head = current;
if (head != NULL) {
head->prev = NULL;
}
} else {
Node* current = head;
int i;
for (i = 1; i < position && current != NULL; i++) {
current = current->next;
}
if (current != NULL) {
if (current->prev != NULL) {
current->prev->next = current->next;
}
if (current->next != NULL) {
current->next->prev = current->prev;
}
free(current);
} else {
printf("Error: invalid position.\n");
}
}
return head;
}
//查找指定节点
Node* search(Node* head, int key) {
Node* current = head;
while (current != NULL) {
if (current->data == key) {
printf("Node with data %d found.\n", key);
return current;
}
current = current->next;
}
printf("Node with data %d not found.\n", key);
return NULL;
}
//打印所有节点
void printList(Node* head) {
Node* current = head;
printf("List: ");
while (current != NULL) {
printf("%d ", current->data);
current = current->next;
}
printf("\n");
}
//主函数
int main() {
Node* head = NULL;
int choice, value, position;
do {
//菜单
printf("\n\n##### MENU #####\n");
printf("1. Insert at head\n");
printf("2. Insert at tail\n");
printf("3. Insert at position\n");
printf("4. Delete at position\n");
printf("5. Search\n");
printf("6. Print list\n");
printf("7. Exit\n");
printf("Enter your choice: ");
scanf("%d", &choice);
//根据选择执行相应操作
switch(choice) {
case 1:
printf("Enter value to insert: ");
scanf("%d", &value);
head = insertAtHead(head, value);
break;
case 2:
printf("Enter value to insert: ");
scanf("%d", &value);
head = insertAtTail(head, value);
break;
case 3:
printf("Enter position: ");
scanf("%d", &position);
printf("Enter value to insert: ");
scanf("%d", &value);
head = insertAtPosition(head, value, position);
break;
case 4:
printf("Enter position: ");
scanf("%d", &position);
head = deleteAtPosition(head, position);
break;
case 5:
printf("Enter value to search: ");
scanf("%d", &value);
search(head, value);
break;
case 6:
printList(head);
break;
case 7:
printf("Exiting...\n");
break;
default:
printf("Invalid choice.\n");
}
} while(choice != 7);
return 0;
}