使用 C 语言实现:使用结构体和指针存储线性表结构求链表节点总数、添加新节点、输出所有节点、任意位置插入新节点、删除节 点、查找节点

在C语言中，可以使用结构体和指针来实现链表的基本操作。下面是一些关键步骤：

1. **定义结构体（Node）**:

typedef struct Node {
    int data;        // 节点数据
    struct Node* next; // 指向下一个节点的指针
} Node;

2. **计算节点总数（链表长度）**:

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

3. **添加新节点**:

void add_node(Node** head, int data, int position) {
    Node* newNode = (Node*)malloc(sizeof(Node));
    newNode->data = data;
    newNode->next = *head;
    
    if (position == 0) {
        *head = newNode;
    } else {
        Node* prev = *head;
        for (int i = 1; i < position - 1 && prev != NULL; i++) {
            prev = prev->next;
        }
        if (prev != NULL) {
            newNode->next = prev->next;
            prev->next = newNode;
        }
    }
}

4. **输出所有节点**:

void print_list(Node* head) {
    if (head == NULL) {
        printf("List is empty.\n");
    } else {
        Node* current = head;
        while (current != NULL) {
            printf("%d -> ", current->data);
            current = current->next;
        }
        printf("NULL\n");
    }
}

5. **任意位置插入新节点**:
已包含在上述`add_node`函数中。

6. **删除节点**:

void delete_node(Node** head, int data) {
    if (*head == NULL) {
        return;
    }

    Node* current = *head;
    if (current->data == data) {
        *head = current->next;
        free(current);
        return;
    }

    Node* prev = current;
    while (current->next != NULL && current->data != data) {
        prev = current;
        current = current->next;
    }

    if (current->data == data) {
        prev->next = current->next;
        free(current);
    }
}

7. **查找节点**:

Node* search_node(Node* head, int data) {
    Node* current = head;
    while (current != NULL) {
        if (current->data == data) {
            return current;
        }
        current = current->next;
    }
    return NULL;
}