How to create and use linked lists in the C programming language?

1 year ago
Jackson Davis
3 minutes

The steps to create a linked list are as follows:

  1. Define a struct to represent a node of a linked list, which includes a data field and a pointer to the next node.
  2. Create a pointer pointing to the head node of the linked list.
  3. Dynamically allocate memory to create a linked list node, and store data in the node’s data field.
  4. Insert the newly created node into the linked list.

The general steps for using a linked list are as follows:

  1. Start from the head node of the linked list and access each node in the list by following the pointers.
  2. Output or process the value of the data field of a node.
  3. Point the pointer to the next node and continue looping until reaching the end of the linked list, which is when the pointer is empty.
  4. Create a new node and allocate memory for it.
  5. Save the data into the data field of the new node.
  6. Adjust the pointers of the nodes in the linked list to insert the new node into the appropriate position.
  7. Find the node before the one you want to delete.
  8. Adjust the pointers of the nodes to skip the node to be deleted.
  9. Release the memory of the deleted node.

Here is a simple example code using a linked list implementation:

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

// 定义链表节点结构体
typedef struct Node {
    int data;           // 数据域
    struct Node *next;  // 指向下一个节点的指针
} Node;

// 创建链表节点
Node* createNode(int data) {
    Node* newNode = (Node*)malloc(sizeof(Node));
    if (newNode == NULL) {
        printf("内存分配失败！\n");
        exit(1);
    }
    newNode->data = data;
    newNode->next = NULL;
    return newNode;
}

// 插入节点到链表末尾
void insertNode(Node** head, int data) {
    Node* newNode = createNode(data);    // 创建新节点
    if (*head == NULL) {
        *head = newNode;    // 若链表为空，则新节点为头节点
    } else {
        Node* current = *head;
        while (current->next != NULL) {
            current = current->next;    // 遍历链表直到最后一个节点
        }
        current->next = newNode;    // 将新节点插入到链表末尾
    }
}

// 删除指定值的节点
void deleteNode(Node** head, int data) {
    Node* current = *head;
    Node* previous = NULL;
    while (current != NULL) {
        if (current->data == data) {
            if (previous == NULL) {
                *head = current->next;    // 如果要删除的节点是头节点
            } else {
                previous->next = current->next;    // 跳过当前节点
            }
            free(current);    // 释放被删除节点的内存
            return;
        }
        previous = current;
        current = current->next;
    }
    printf("要删除的节点不存在！\n");
}

// 遍历链表并输出节点的值
void traverseList(Node* head) {
    Node* current = head;
    printf("链表节点的值：");
    while (current != NULL) {
        printf(" %d", current->data);
        current = current->next;
    }
    printf("\n");
}

int main() {
    Node* head = NULL;    // 头节点指针初始化为空
    insertNode(&head, 1);
    insertNode(&head, 2);
    insertNode(&head, 3);
    insertNode(&head, 4);
    insertNode(&head, 5);
    traverseList(head);    // 输出链表节点的值

    deleteNode(&head, 3);
    traverseList(head);

    return 0;
}

The above is a basic example of linked list operations, including creating nodes, inserting nodes, deleting nodes, and traversing the list. It can be expanded and modified according to actual needs.

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