C++实现单链表增删改查

单链表是一种常用的数据结构，它由一系列节点组成，每个节点包含一个数据元素和一个指向下一个节点的指针。单链表的操作包括增加节点、删除节点、修改节点和查找节点。下面是C语言实现单链表的增删改查示例代码：

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

// 节点结构体
typedef struct node {
    int data;  // 数据元素
    struct node* next;  // 指向下一个节点的指针
} Node;

// 在单链表末尾增加节点
void addNode(Node** head, int data) {
    Node* newNode = (Node*)malloc(sizeof(Node));
    newNode->data = data;
    newNode->next = NULL;

    if (*head == NULL) {
        *head = newNode;
    } else {
        Node* current = *head;
        while (current->next != NULL) {
            current = current->next;
        }
        current->next = newNode;
    }
}

// 在单链表指定位置插入节点
void insertNode(Node** head, int index, int data) {
    Node* newNode = (Node*)malloc(sizeof(Node));
    newNode->data = data;

    if (index == 0) {
        newNode->next = *head;
        *head = newNode;
    } else {
        Node* current = *head;
        for (int i = 0; i < index - 1 && current != NULL; i++) {
            current = current->next;
        }
        if (current != NULL) {
            newNode->next = current->next;
            current->next = newNode;
        } else {
            printf("Index out of range\n");
        }
    }
}

// 在单链表指定位置删除节点
void deleteNode(Node** head, int index) {
    if (*head == NULL) {
        printf("List is empty\n");
        return;
    }

    Node* current = *head;
    Node* previous = NULL;

    if (index == 0) {
        *head = current->next;
        free(current);
    } else {
        for (int i = 0; i < index && current != NULL; i++) {
            previous = current;
            current = current->next;
        }
        if (current != NULL) {
            previous->next = current->next;
            free(current);
        } else {
            printf("Index out of range\n");
        }
    }
}

// 修改单链表指定位置节点的值
void modifyNode(Node* head, int index, int data) {
    if (head == NULL) {
        printf("List is empty\n");
        return;
    }

    Node* current = head;
    for (int i = 0; i < index && current != NULL; i++) {
        current = current->next;
    }
    if (current != NULL) {
        current->data = data;
    } else {
        printf("Index out of range\n");
    }
}

// 查找单链表指定位置节点的值
int searchNode(Node* head, int index) {
    if (head == NULL) {
        printf("List is empty\n");
        return -1;
    }

    Node* current = head;
    for (int i = 0; i < index && current != NULL; i++) {
        current = current->next;
    }
    if (current != NULL) {
        return current->data;
    } else {
        printf("Index out of range\n");
        return -1;
    }
}

// 打印单链表
void printList(Node* head) {
    if (head == NULL) {
        printf("List is empty\n");
        return;
    }

    Node* current = head;
    printf("List: ");
    while (current != NULL) {
        printf("%d ", current->data);
        current = current->next;
    }
    printf("\n");
}

int main() {
    Node* head = NULL;

    // 在单链表末尾增加节点
    addNode(&head, 1);
    addNode(&head, 2);
    addNode(&head, 3);
    printList(head);

    // 在单链表指定位置插入节点
    insertNode(&head, 1, 4);
    insertNode(&head, 0, 5);
    insertNode(&head, 6, 6);
    printList(head);

    // 在单链表指定位置删除节点
    deleteNode(&head, 2);
    deleteNode(&head, 0);
    deleteNode(&head, 4);
    printList(head);

    // 修改单链表指定位置节点的值
    modifyNode(head, 1, 7);
    modifyNode(head, 3, 8);
    modifyNode(head, 5, 9);
    printList(head);

    // 查找单链表指定位置节点的值
    printf("Value at index 2: %d\n", searchNode(head, 2));
    printf("Value at index 5: %d\n", searchNode(head, 5));
    printf("Value at index 7: %d\n", searchNode(head, 7));

    return 0;
}