C语言链表动态创建：头插法与尾插法详解

一、引言

在学习C语言的过程中，链表是一个非常重要的数据结构。本文将详细介绍如何使用C语言动态创建链表，并重点讲解头插法和尾插法的具体实现。通过这些方法，我们可以更灵活地管理链表中的节点。

二、头插法

头插法是指每次插入的新节点都作为链表的头部。具体实现如下：

// 动态创建链表（头插法）
struct Node *insertAtHead(struct Node *head) {
    struct Node *newNode;
    while (1) {
        newNode = (struct Node *)malloc(sizeof(struct Node));
        printf("请输入新节点的数据:\n");
        scanf("%d", &newNode->data);
        if (newNode->data == 0) {
            printf("输入0退出！\n");
            return head;
        }
        if (head == NULL) {
            head = newNode;
            newNode->next = NULL;
        } else {
            newNode->next = head;
            head = newNode;
        }
    }
    return head;
}

三、尾插法

尾插法是指每次插入的新节点都作为链表的尾部。具体实现如下：

// 动态创建链表（尾插法）
struct Node *insertAtTail(struct Node *head) {
    struct Node *newNode, *temp = head;
    while (1) {
        newNode = (struct Node *)malloc(sizeof(struct Node));
        printf("请输入新节点的数据:\n");
        scanf("%d", &newNode->data);
        if (newNode->data == 0) {
            printf("输入0退出！\n");
            return head;
        }
        if (head == NULL) {
            head = newNode;
            newNode->next = NULL;
        } else {
            while (temp->next != NULL)
                temp = temp->next;
            temp->next = newNode;
            newNode->next = NULL;
        }
    }
    return head;
}

四、示例源码

以下是完整的示例源码，包含链表的遍历、计数、查询、插入和删除等基本操作：

#include 
#include 

struct Node {
    int data;
    struct Node *next;
};

void traverseList(struct Node *head) {
    while (head != NULL) {
        printf("%d ", head->data);
        head = head->next;
    }
    putchar('\n');
}

int countNodes(struct Node *head) {
    int count = 0;
    while (head != NULL) {
        count++;
        head = head->next;
    }
    return count;
}

int searchNode(struct Node *head, int target) {
    while (head != NULL) {
        if (head->data == target)
            return 1;
        head = head->next;
    }
    return 0;
}

struct Node *insertAfter(struct Node *head, int target, struct Node *newNode) {
    while (head != NULL) {
        if (head->data == target) {
            newNode->next = head->next;
            head->next = newNode;
            return head;
        }
        head = head->next;
    }
    return head;
}

struct Node *insertBefore(struct Node *head, int target, struct Node *newNode) {
    if (head == NULL || head->data == target) {
        newNode->next = head;
        return newNode;
    }
    struct Node *prev = head;
    while (prev->next != NULL && prev->next->data != target)
        prev = prev->next;
    if (prev->next != NULL) {
        newNode->next = prev->next;
        prev->next = newNode;
        return head;
    }
    return head;
}

struct Node *deleteNode(struct Node *head, int target) {
    if (head == NULL)
        return head;
    if (head->data == target)
        return head->next;
    struct Node *prev = head;
    while (prev->next != NULL && prev->next->data != target)
        prev = prev->next;
    if (prev->next != NULL) {
        struct Node *toDelete = prev->next;
        prev->next = prev->next->next;
        free(toDelete);
    }
    return head;
}

struct Node *insertAtHead(struct Node *head) {
    struct Node *newNode;
    while (1) {
        newNode = (struct Node *)malloc(sizeof(struct Node));
        printf("请输入新节点的数据:\n");
        scanf("%d", &newNode->data);
        if (newNode->data == 0) {
            printf("输入0退出！\n");
            return head;
        }
        if (head == NULL) {
            head = newNode;
            newNode->next = NULL;
        } else {
            newNode->next = head;
            head = newNode;
        }
    }
    return head;
}

struct Node *insertAtTail(struct Node *head) {
    struct Node *newNode, *temp = head;
    while (1) {
        newNode = (struct Node *)malloc(sizeof(struct Node));
        printf("请输入新节点的数据:\n");
        scanf("%d", &newNode->data);
        if (newNode->data == 0) {
            printf("输入0退出！\n");
            return head;
        }
        if (head == NULL) {
            head = newNode;
            newNode->next = NULL;
        } else {
            while (temp->next != NULL)
                temp = temp->next;
            temp->next = newNode;
            newNode->next = NULL;
        }
    }
    return head;
}

int main() {
    struct Node *head = NULL;
    head = insertAtTail(head);
    traverseList(head);
    return 0;
}

五、程序运行

以下为尾插法的运行示例：