用C语言编程实现单向链表的基本操作： 1．插入元素2．删除元素 3．获取第 i 个结点的数据元素 4．判断元素是否存在 5．获取某个元素的下一个元素； NextElem ( L , cur _ e ,& next _ e );

1.插入元素

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

void insertNode(Node **head, int data) {
    Node *newNode = (Node*)malloc(sizeof(Node));
    newNode->data = data;
    newNode->next = NULL;
    if (*head == NULL) {
        *head = newNode;
    } else {
        Node *p = *head;
        while (p->next != NULL) {
            p = p->next;
        }
        p->next = newNode;
    }
}

2.删除元素

void deleteNode(Node **head, int data) {
    if (*head == NULL) {
        return;
    }
    Node *p = *head;
    if (p->data == data) {
        *head = p->next;
        free(p);
        return;
    }
    while (p->next != NULL && p->next->data != data) {
        p = p->next;
    }
    if (p->next != NULL) {
        Node *q = p->next;
        p->next = q->next;
        free(q);
    }
}

3.获取第 i 个结点的数据元素

int getData(Node *head, int i) {
    if (head == NULL) {
        return -1;
    }
    int cnt = 1;
    Node *p = head;
    while (p != NULL && cnt != i) {
        p = p->next;
        cnt++;
    }
    if (p == NULL) {
        return -1;
    } else {
        return p->data;
    }
}

4.判断元素是否存在

bool isExist(Node *head, int data) {
    if (head == NULL) {
        return false;
    }
    Node *p = head;
    while (p != NULL) {
        if (p->data == data) {
            return true;
        }
        p = p->next;
    }
    return false;
}

5.获取某个元素的下一个元素； NextElem ( L , cur _ e )

int getNextElem(Node *head, int data) {
    if (head == NULL) {
        return -1;
    }
    Node *p = head;
    while (p != NULL) {
        if (p->data == data && p->next != NULL) {
            return p->next->data;
        }
        p = p->next;
    }
    return -1;
}