数据结构单链表的基本操作代码C语言

1. 定义单链表结构体和节点结构体

typedef struct ListNode {
    int data;
    struct ListNode *next;
} ListNode;

typedef struct LinkedList {
    ListNode *head;
    int length;
} LinkedList;

2. 创建一个空链表

LinkedList *createLinkedList() {
    LinkedList *list = (LinkedList *)malloc(sizeof(LinkedList));
    list->head = NULL;
    list->length = 0;
    return list;
}

3. 在链表尾部插入一个节点

void insertAtTail(LinkedList *list, int data) {
    ListNode *newNode = (ListNode *)malloc(sizeof(ListNode));
    newNode->data = data;
    newNode->next = NULL;

    if (list->head == NULL) {
        list->head = newNode;
    } else {
        ListNode *tail = list->head;
        while (tail->next != NULL) {
            tail = tail->next;
        }
        tail->next = newNode;
    }

    list->length++;
}

4. 在链表头部插入一个节点

void insertAtHead(LinkedList *list, int data) {
    ListNode *newNode = (ListNode *)malloc(sizeof(ListNode));
    newNode->data = data;
    newNode->next = list->head;

    list->head = newNode;
    list->length++;
}

5. 在链表中间插入一个节点

void insertAtIndex(LinkedList *list, int index, int data) {
    if (index < 0 || index > list->length) {
        printf("Error: index out of range.\n");
        return;
    }

    if (index == 0) {
        insertAtHead(list, data);
        return;
    }

    if (index == list->length) {
        insertAtTail(list, data);
        return;
    }

    ListNode *newNode = (ListNode *)malloc(sizeof(ListNode));
    newNode->data = data;

    ListNode *prev = list->head;
    for (int i = 0; i < index - 1; i++) {
        prev = prev->next;
    }

    newNode->next = prev->next;
    prev->next = newNode;

    list->length++;
}

6. 获取链表中指定位置的节点值

int get(LinkedList *list, int index) {
    if (index < 0 || index >= list->length) {
        printf("Error: index out of range.\n");
        return -1;
    }

    ListNode *current = list->head;
    for (int i = 0; i < index; i++) {
        current = current->next;
    }
    return current->data;
}

7. 修改链表中指定位置的节点值

void set(LinkedList *list, int index, int data) {
    if (index < 0 || index >= list->length) {
        printf("Error: index out of range.\n");
        return;
    }

    ListNode *current = list->head;
    for (int i = 0; i < index; i++) {
        current = current->next;
    }
    current->data = data;
}

8. 删除链表中指定位置的节点

void deleteAtIndex(LinkedList *list, int index) {
    if (index < 0 || index >= list->length) {
        printf("Error: index out of range.\n");
        return;
    }

    ListNode *deletedNode = NULL;

    if (index == 0) {
        deletedNode = list->head;
        list->head = list->head->next;
    } else {
        ListNode *prev = list->head;
        for (int i = 0; i < index - 1; i++) {
            prev = prev->next;
        }
        deletedNode = prev->next;
        prev->next = deletedNode->next;
    }

    free(deletedNode);
    list->length--;
}

9. 判断链表是否为空

bool isEmpty(LinkedList *list) {
    return list->head == NULL;
}

10. 获取链表的长度

int length(LinkedList *list) {
    return list->length;
}