【重拾C语言】十三、动态数据组织（二）链表（创建、遍历检索、插入、删除、交换）

// 定义节点结构
struct Node {
    int data;           // 数据成员
    struct Node* next;  // 指针成员
};

// 创建链表
struct Node* createLinkedList() {
    struct Node* head = NULL;  // 头指针，指向链表的第一个节点
    struct Node* temp = NULL;  // 临时指针，用于创建新节点
    
    // 创建节点1
    struct Node* node1 = (struct Node*)malloc(sizeof(struct Node));
    node1->data = 1;
    node1->next = NULL;
    
    // 将节点1设为头节点
    head = node1;
    
    // 创建节点2
    struct Node* node2 = (struct Node*)malloc(sizeof(struct Node));
    node2->data = 2;
    node2->next = NULL;
    
    // 将节点2链接到节点1后面
    node1->next = node2;
    
    // 创建节点3
    struct Node* node3 = (struct Node*)malloc(sizeof(struct Node));
    node3->data = 3;
    node3->next = NULL;
    
    // 将节点3链接到节点2后面
    node2->next = node3;
    
    return head;  // 返回头指针
}

// 遍历链表并打印节点数据
void traverseLinkedList(struct Node* head) {
    struct Node* current = head;  // 从头节点开始遍历
    
    while (current != NULL) {
        printf("%d ", current->data);  // 打印节点数据
        current = current->next;      // 移动到下一个节点
    }
}

// 在链表中插入节点
void insertNode(struct Node* prevNode, int newData) {
    if (prevNode == NULL) {
        printf("Error: Previous node cannot be NULL.\n");
        return;
    }
    
    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
    newNode->data = newData;
    newNode->next = prevNode->next;
    prevNode->next = newNode;
}

// 在链表中删除节点
void deleteNode(struct Node* prevNode) {
    if (prevNode == NULL || prevNode->next == NULL) {
        printf("Error: Node to be deleted cannot be NULL.\n");
        return;
    }
    
    struct Node* nodeToDelete = prevNode->next;
    prevNode->next = nodeToDelete->next;
    free(nodeToDelete);  // 释放内存
}

// 在链表中交换两个节点的位置
void swapNodes(struct Node* head, int data1, int data2) {
    if (data1 == data2) {
        printf("Error: Data values are the same.\n");
        return;
    }
    
    struct Node* prevNode1 = NULL;
    struct Node* prevNode2 = NULL;
    struct Node* currentNode = head;
    
    while (currentNode != NULL) {
        if (currentNode->next != NULL && currentNode->next->data == data1)
            prevNode1 = currentNode;
        if (currentNode->next != NULL && currentNode->next->data == data2)
            prevNode2 = currentNode;
        
        currentNode = currentNode->next;
    }
    
    if (prevNode1 == NULL || prevNode2 == NULL) {
        printf("Error: Data values not found in the list.\n");
        return;
    }
    
    struct Node* node1 = prevNode1->next;
    struct Node* node2 = prevNode2->next;
    
    if (prevNode1 != NULL)
        prevNode1->next = node2;
    else
        head = node2;
    
    if (prevNode2 != NULL)
        prevNode2->next = node1;
    else
        head = node1;
    
    struct Node* temp = node1->next;
    node1->next = node2->next;
    node2->next = temp;
}

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

struct Task {
    char name[100];
    struct Task* next;
};

struct Task* createTask(const char* name) {
    struct Task* task = (struct Task*)malloc(sizeof(struct Task));
    strcpy(task->name, name);
    task->next = NULL;
    return task;
}

void addTask(struct Task** head, const char* name) {
    struct Task* newTask = createTask(name);
    if (*head == NULL) {
        *head = newTask;
    } else {
        struct Task* current = *head;
        while (current->next != NULL) {
            current = current->next;
        }
        current->next = newTask;
    }
}

void printTasks(struct Task* head) {
    struct Task* current = head;
    while (current != NULL) {
        printf("%s\n", current->name);
        current = current->next;
    }
}

int main() {
    struct Task* taskList = NULL;
    
    addTask(&taskList, "Task 1");
    addTask(&taskList, "Task 2");
    addTask(&taskList, "Task 3");
    
    printTasks(taskList);
    
    return 0;
}

Task 1
Task 2
Task 3