单链表

本文为个人学习笔记。简单的单链表实现。

　　实现过程中到的问题：

　　①：定义指针要赋值，或者new一个新的空间。

　　②：delete 不能随便用。。。

先来两张常见基本指针操作截图，再上代码

 

头文件：

#include <iostream>
using namespace std;

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

class List
{
    Node* head;
public:
    List(){head = NULL; length = 0;}
    ~List(){};

    void Init();
    void Insertlist(int _data,unsigned int _location);
    void Deletelist(unsigned int _location);

    void Printlist();
    void Emptylist();

    int Findkth(unsigned int k);//找到第K个数据
    int Find(int m_num,unsigned int k);//找到第k个m_num的位置

private:
    Node* m_node;//最后一个元素
    unsigned int length;
};

cpp文件：

#include "list.h"

int main()
{
    List linkedlist;

    linkedlist.Init();
    int i = 1;
    while (i)
    {
        cout<<"1:插入；2：删除；3：输出；4:清空；5：查数；6：查位置；0:退出"<<endl;
        cin>>i;
        switch (i)
        {
        int data;unsigned int location;
        case 0: return 0;
        case 1:cout<<"请输入要插入的数据和位置"<<endl;
                    cin>>data>>location;
                    linkedlist.Insertlist(data,location);
                    continue;
        case 2:cout<<"请输入要删除的位置："<<endl;
                    cin>>location;
                    linkedlist.Deletelist(location);
                    continue    ;
        case 3:linkedlist.Printlist();
                    continue;
        case 4:linkedlist.Emptylist();
                    continue;
        case 5:cout<<"请输入要查找数据的位置："<<endl;
                    cin>>location;
                    cout<<linkedlist.Findkth(location)<<endl;;
                    continue;
        case 6:cout<<"输入num和k"<<endl;
                    cin>>data>>location;
                    cout<<linkedlist.Find(data,location)<<endl;
                    continue    ;
            break;
        }
    }

}

//*********************
//初始化链表
//*********************
void List::Init()
{
    m_node = new Node;//此处要new一个新的空间
    cout<<"输入初始化元素,并以0结束 "<<endl;
    int init_data = 0;
    while(cin>>init_data)
    {
        if (init_data == 0)
        {
            break;
        }
        
        if(length == 0)
        {
            m_node->data = init_data;
            m_node->next = NULL;
            head = m_node;
        }
        else
        {
            Node* m_temp = new Node;
            m_temp->data = init_data;
            m_node->next = m_temp;
            m_node = m_temp;
            m_node->next = NULL;
        }
        length++;
    }
//    delete m_node;//这将会将最后一个节点也删除点
}

//*********************
//_data为要插入的数
//_location为插入位置
//*********************
void List::Insertlist(int _data,unsigned int _location)
{
    if(_location > length+1)
    {
        cout<<"位置太大，请输入新的数据和位置"<<endl;
        cin>>_data>>_location;
        Insertlist(_data,_location);
    }
    else if (_location == 1)
    {
        Node* m_temp = new Node;
        m_temp->data = _data;
        m_temp->next = head;
        head = m_temp;

        length++;
    } 
    else
    {
        unsigned int n = 1;
        Node* m_temp = new Node;
        m_node = head;

        while (n < _location - 1)
        {
            m_node = m_node->next;
            n++;
        }
        
        m_temp->data = _data;
        m_temp->next = m_node->next;
        m_node->next = m_temp;

        length++;
    }
}

//*********************
//_location为删除位置
//*********************
void List::Deletelist(unsigned int _location)
{
    if(_location > length+1)
    {
        cout<<"位置太大，请输入新的位置"<<endl;
        cin>>_location;
        Deletelist(_location);
    }
    else if (_location == 1)
    {
        m_node = head;
        head = head->next;
        delete m_node;
        length--;
    } 
    else
    {
        unsigned int n = 1;
        Node* m_temp = new Node;
        m_node = head;

        while (n < _location - 1)
        {
            m_node = m_node->next;
            n++;
        }

        m_temp = m_node->next;
        m_node->next = m_temp->next;
        delete m_temp;
        length--;
    }
}
//*********************
//输出链表
//*********************
void List::Printlist()
{
    Node* m_temp = head;
    while(m_temp)
    {
        cout<<m_temp->data<<"	";
        m_temp = m_temp->next;
    }
    cout<<endl;
}
//*********************
//清空链表
//*********************
void List::Emptylist()
{
    Node* m_temp = head;
    while(m_temp)
    {
        head = m_temp->next;
        delete m_temp;
        m_temp = head;
    }
    length = 0;
    cout<<endl;
}

//*********************
//查找第k个数
//*********************
int List::Findkth(unsigned int k)
{
    if (k>length)
    {
        cout<<"没找到这个位置，请重新输入：
";
        cin>>k;
        Findkth(k);
    }
    else
    {
        m_node = head;
        for (unsigned int i = 1;i<k;i++)
        {
            m_node = m_node->next;
        }
        return m_node->data;
    }
    cout<<"false!
";
    return 0;
}

//*********************
////找到第k个m_num的位置
//*********************
int List::Find(int m_num,unsigned int k)
{
    if (k>length)
    {
        cout<<"没找到第"<<k<<"个"<<m_num<<"，请重新输入：
";
        cin>>m_num>>k;
        Find(m_num,k);
    }
    else
    {
        m_node = head;
        int i = 0,j = 0;
        for (;i != length;i++)
        {
            if (m_node->data == m_num)
            {
                j++;
                if (j == k)
                {
                    return i+1;
                }
            }
            m_node = m_node->next;
        }
        cout<<"false
";
        return -1;
    }
}