STL

#include<iostream>
#include<list>

using namespace std;
// list 构造函数
void test01()
{
    list<int> lst1;
    lst1.push_back(10);
    lst1.push_back(20);
    lst1.push_back(30);
    list<int> lst2(lst1);//拷贝构造函数
    list<int> lst3(5, 10);//构造函数
    list<int> lst4;
    lst4.assign(lst3.begin(), lst3.end());
}

// list 数据元素的插入与删除操作
void test02()
{
    list<int> lst1;
    lst1.push_back(30);
    lst1.push_front(20);//20 30
    lst1.insert(lst1.begin(), 10);//10 20 30  // 相当于 push_front
    lst1.insert(lst1.end(), 40);//10 20 30 40 // 相当于 push_back
    list<int>::iterator itr = lst1.begin();
    itr++;
    itr++;
    lst1.insert(itr, 999);//10 20 999 30 40
    lst1.push_back(999); //10 20 999 30 40 999
    auto itr_ = lst1.begin();
    itr_++;
    lst1.erase(lst1.begin(), itr_);// [ , )左闭右开  20 999 30 40 999
    lst1.remove(999);//删除容器中所有值为999的元素    20 30 40 
}
int main()
{
    test01();
    test02();
    return 1;
}

 　　链表每个节点都有一个指针，结果是：链表插入与删除效率比线性表高，但是内存开销大，同时链表节点遍历相对线性表慢。

链表的c语言实现版本：

#include<iostream>
#include<set>
using namespace std;

class Node
{
public:
    int data_;//数据阈
    Node* next_;//指针阈
public:
    Node():data_(-1), next_(nullptr) {}
};

class List
{
public:
    List()
    {
        this->head_ = new Node();// 不分配空间，下面赋值是不合理的！
                                 //this->head_->data_ = 0;//多余？
        this->head_->next_ = nullptr;
        this->size_ = 0;
    };
    void insert(int pos, int value);
    void remove(int pos);
    int get_reverse_element(int reverse_pos);//链表中倒数第k个节点
    void reverse();

    int operator[](int i);
    void print();
    ~List();


public:
    Node* head_;
    int size_;//维护一个size
};
//在第pos个元素前一个位置插入（创建、找到位置、入链表）
void List::insert(int pos, int value)
{
    if (pos < 0 || pos > size_)
        return;

    //创建新的节点接受数据
    Node* newnode = new Node();
    newnode->data_ = value;
    //cout << "newnode->data_ = " << *newnode->data_ << endl;
    newnode->next_ = nullptr;

    //利用辅助指针找到pos前一个节点
    // 其实这里不断next，无非就是希望p_curr = nullptr
    // 然后56行 让newnode->next_  = nullptr（这个nullptr是从head_->next 传过来的）；也就是尾部插入嘛
    // 而循环链表 同理 让newnode->next_  = &(head_)（这个 &(head_) 是从head_->next 传过来的）；
    Node* p_curr = head_;
    for (int i = 0; i < pos; i++) //这个for循环本质上是head_->next_->next_......
    {
        p_curr = p_curr->next_;
    }
    //现在p_curr就是pos前一个节点的指针阈
    //新节点入链表
    newnode->next_ = p_curr->next_;//右边
    p_curr->next_ = newnode;//左边
    size_++;
}

void List::remove(int pos)
{
    if (pos < 0 || pos > size_)
    {
        return;
    }
    Node* p_curr = head_;
    for (int i = 0; i < pos; i++)// 3
    {
        p_curr = p_curr->next_;
    }
    p_curr->next_ = p_curr->next_->next_;
    size_--;
}

//链表中倒数第k个节点
int List::get_reverse_element(int reverse_pos)
{
    int pos = size_ - reverse_pos;
    Node* p_curr = head_;
    for (int i = 0; i < pos; i++)
    {
        p_curr = p_curr->next_;
    }
    return p_curr->data_;
}

//反转链表
void List::reverse()
{
    // head   -> 1 -> 2 -> 3 -> 4 -> nullptr
    //nullptr <- 1 <- 2 <- 3 <- 4

    Node* p_curr = head_->next_;
    Node* p_prev = nullptr;
    while (p_curr != nullptr)
    {
        Node* p_next = p_curr->next_;
        if(p_curr->next_ == nullptr)
        {
            head_->next_ = p_curr;
        }
        p_curr->next_ = p_prev;
        p_prev = p_curr;
        p_curr = p_next;
    }
}

int List::operator[](int i)
{
    Node* p_curr = head_;
    int count = 0;
    while (count <= i)
    {
        p_curr = p_curr->next_;
        count++;
    }
    return p_curr->data_;
}
void List::print()
{
    if (size_ == 0)
    {
        cout << "size = 0" << endl;
        return;
    }
    //遍历
    Node* p_curr = head_->next_;//【注意这里next】
    while (p_curr != nullptr)
    {
        cout << p_curr->data_ << " ";
        p_curr = p_curr->next_;
    }
    cout << endl;
}
List::~List()
{
    while (size_ != 0)
    {
        Node* p_curr = head_;
        for (int i = 0; i < (size_ - 1); i++)// 012345 i < 5
        {
            p_curr = p_curr->next_;//for循环执行完，p_curr指向4
        }
        delete p_curr->next_;//删除最后一个元素
        p_curr->next_ = nullptr;//末尾元素 空指针
        size_--;
        print();
    }
    delete head_; //【这个容易忘记！】
    cout << "delete!" << endl;
}

//合并两个排序链表
void mergeLists(List& list3, List& list4, List& list34)
{
    Node* p_curr3 = list3.head_->next_;
    Node* p_curr4 = list4.head_->next_;
    Node* p_curr34 = list34.head_->next_;
    int location = 0;
    while ((p_curr3 != nullptr) || (p_curr4 != nullptr))
    {
        if ((p_curr3 != nullptr) && (p_curr4 != nullptr))
        {
            if (p_curr3->data_ < p_curr4->data_)
            {
                list34.insert(location, p_curr3->data_);
                location++;
                list34.insert(location, p_curr4->data_);
                location++;
            }
            else
            {
                list34.insert(location, p_curr4->data_);
                location++;
                list34.insert(location, p_curr3->data_);
                location++;
            }
            p_curr3 = p_curr3->next_;
            p_curr4 = p_curr4->next_;
        }
        else if ((p_curr3 != nullptr) && (p_curr4 == nullptr))
        {
            list34.insert(location, p_curr3->data_);
            location++;
            p_curr3 = p_curr3->next_;
        }
        else if ((p_curr3 == nullptr) && (p_curr4 != nullptr))
        {
            list34.insert(location, p_curr4->data_);
            location++;
            p_curr4 = p_curr4->next_;
        }
    }
}


int main()
{
    List list1;
    //插入
    for (int i = 0; i < 15; i++)
    {
        list1.insert(i, i);
    }

    //删除
    list1.remove(10);
    list1.remove(5);
    //打印
    list1.print();
    list1.reverse();
    list1.print();
    //访问倒数元素
    for (int i = 1; i < 4; i++)
    {
        cout << "倒数第" << i << "个元素是：" << list1.get_reverse_element(i) << endl;
    }
    list1.insert(2, 9999);
    //重载符[]
    for (int i = list1.size_ - 1; i >= 0; i--)
    {
        cout << list1[i] << " ";
    }
    cout << endl;
    List list2;
    list2.insert(0, 10);
    list2.insert(1, 20);
    list2.insert(2, 30);
    list2.print();
    int size2 = list2.size_;

    //合并两个排序链表
    List list3, list4;
    for (int i = 0; i < 5; i++)
    {
        list3.insert(i, 2 * i);
        list4.insert(i, 2 * i + 1);
    }
    list4.insert(5, 12);
    list4.insert(6, 21);
    list3.print();
    list4.print();

    List list34;
    mergeLists(list3, list4, list34);
    list34.print();


    return 1;
}