#include <iostream>
#include <stdlib.h>
 
using namespace std;
 
class List
{
public:
    List();
    ~List();
    List* createNode(int value);//创建节点
    bool insertNode(List *node);//插入节点
    void printList();//打印节点
    bool deleteNode(List *node);//删除节点不移动头节点
    bool deleteNode1(List *node);//删除节点移动头节点
    int listSize();//长度
    void printNode();//打印但前的value
    void freeList();//释放链表
private:
    int value;
    List *head;
    List *next;
};
 
bool List::deleteNode(List *node)
{
    if (node == NULL)
    {
        std:cout << "node is NULL" << std::endl;    
        return false;
    }
    if (head == NULL)
    {
        std::cout << "head is NULL" << std::endl;   
        return false;
    }
    //如果node等于head
    if (head == node)
    {
        head = head->next;
    }
    List *p = head;
    while (p->next != NULL)
    {
        if (p->next == node)
        {
            p->next = p->next->next;
            return true;
        }
        p = p->next;
    }
    return false;   
}
 
bool List::deleteNode1(List *node)
{
    if (node == NULL)
    {
        std:cout << "node is NULL" << std::endl;    
        return false;
    }
    if (head == NULL)
    {
        std::cout << "head is NULL" << std::endl;   
        return false;
    }
    //如果node等于head
    if (head == node)
    {
        head = head->next;
    }
    List *p = head;
    while (head->next != NULL)
    {
        if (head->next == node)
        {
            head->next = head->next->next;
            std::cout << "delete node success head->value" << head->value << std::endl;
            //这里要记得把头节点的指针移动最后还原,这里的头节点是保存在这个类里面,改变了就是改变了
            //如果这里是把head作为参数传递,最后head会被销毁那么不需要移动头指针
            head = p;
            return true;
        }
        //注意,这里由于head是成员变量,改变了就是改变了,所以需要最后重新指定
        head = head->next;
    }
    std::cout << "delete node fail head->value" << head->value << std::endl;
    //这里要记得把头节点的指针移动最后还原,这里的头节点是保存在这个类里面,改变了就是改变了
    //如果这里是把head作为参数传递,最后head会被销毁那么不需要移动头指针
    head = p;
    return false;   
}
 
List::List()
{
    value = 0;
    head = NULL;
    next = NULL;
}
 
List::~List()
{
    delete head;
    delete next;
}
 
 
List* List::createNode(int value)
{
    List *list = NULL;
    list = new List();
    if (list)
    {
        list->value = value;
        return list;    
    }
    return NULL;
}
 
bool List::insertNode(List *node)
{
    node->next = head;
    head = node;
    return true;    
}
 
void List::printList()
{   if (head == NULL)
    {
        std::cout << "head is NULL" << std::endl;
        return;
    }
    List *p = head;
    while (p != NULL)
    {
        std::cout << p->value << std::endl; 
        p = p->next;
    }
    return; 
}
 
void List::printNode()
{
    std::cout << value << std::endl;    
}
 
int List::listSize()
{
    if (head == NULL)
    {
        std::cout << "head is NULL" << std::endl;
        return 0;   
    }
    int len = 0;
    List *p = head;
    while (p != NULL)
    {
        p = p->next;
        ++len;
    }
    return len;
}
 
void List::freeList()
{
    if (head == NULL)
    {
        std::cout << "head is NULL" << std::endl;
        return; 
    }
    List *p;
    while (head != NULL)
    {
        p = head;
        head = head->next;
        free(p);
    }
}
 
int main()
{
    List list;
    List *list1 = list.createNode(5);
    list.insertNode(list1);
 
    List *list2 = list.createNode(6);
    list.insertNode(list2);
 
    List *list3 = list.createNode(1);
    list.insertNode(list3);
 
    List *list4 = list.createNode(3);
    list.insertNode(list4);
 
    List *list5 = list.createNode(2);
    list.insertNode(list5);
 
    list.printList();
 
    std::cout << "list size is " << list.listSize() << std::endl;
 
    std::cout << "-----------开始删除节点值为3的节点" << std::endl;
    
    list.deleteNode1(list4);
    list.printList();
    
    std::cout << "list size is " << list.listSize() << std::endl;
 
    list.freeList();
    
    list.printList();
    return 0;   
}