单链表

#include <iostream>
using namespace std;
typedef struct listnode
{
    int data;
    struct listnode *next;
}LIST_NODE;
typedef struct list
{
    LIST_NODE* head;
}LIST;
LIST* create_list()
{
    LIST* list = new (LIST);
    list->head = NULL;
    return list;
}
LIST_NODE* create_node(int data)
{
    LIST_NODE* node = new (LIST_NODE);
    node->data = data;
    node->next = NULL;
}
void list_append(LIST* list, int data)  //类似于 链式存储栈一样
{
    LIST_NODE* node = create_node(data);
    if(NULL==list->head)
    {
        list->head = node;
    }
    else
    {
        node->next = list->head;
        list->head = node;
    }
}
void list_end_append(LIST* list, int data)
{
    LIST_NODE* node =NULL;
    for(node=list->head; node; node=node->next)
    {
        if(NULL==node->next)
        {
            break;
        }
    }
    if(node)
    {
        node->next = create_node(data);
    }
    else
    {
        list->head = create_node(data);
    }
}
void print(LIST* list)
{
    LIST_NODE* node = NULL;
    for(node = list->head;node;node =node->next)
    {
        cout<< node->data <<" ";
    }
    cout<<endl;
}
bool list_insert(LIST* list,int after, int now) //now->after
{
    LIST_NODE* node = NULL;
    for(node=list->head;node;node=node->next)
    {
        if(now == node->data)
        {
            break;
        }
    }
    if(node)
    {
        LIST_NODE*node_new = create_node(after);
        node_new->next =node->next;
        node->next = node_new;
        return true;
    }
    return false;
}
void list_del(LIST* list,int data)
{
    LIST_NODE* front =NULL;
    LIST_NODE* node =list->head;
    while(node)
    {
        if(data == node->data)
        {
            if(node ==list->head)
            {
                list->head = node->next;
                delete(node);
                node =NULL;
                node = list->head;//值为data的node全部删除
            }
            else
            {
                front->next =node->next;
                delete(node);
                node =NULL;
                node = front->next; //值为data的node全部删除
            }
        }
        else
        {
            front =node;
            node=node->next;
        }
    }
}
LIST_NODE* destroy_node(LIST_NODE* node)
{
    LIST_NODE* next = node->next;
    delete(node);
    return next;
}
void destroy_list(LIST* list)
{
    while(list->head)
    {
        list->head = destroy_node(list->head);
    }
    delete(list);
}
void list_reverse(LIST* list)
{
    LIST_NODE* temp = NULL;
    LIST_NODE* new_head = NULL;
    LIST_NODE* node = list->head;
    while(node)
    {
        temp = node;
        node = node->next;
        temp->next =new_head;
        new_head = temp;
    }
    list->head = new_head;
}
LIST_NODE* middle_node(LIST* list)
{
    LIST_NODE* slow = list->head;
    LIST_NODE* fast = list->head;
    while(fast->next && fast->next->next)
    {
        fast = fast->next->next;
        slow = slow->next;
    }
    return slow;
}
bool isCircle(LIST* list)
{
     NODE* slow = list->head;
     NODE* fast = list->head;
    while(fast && fast->next)
    {
          slow = slow->next;
           fast = fast->next->next;
          if(slow == fast)
          {
             break;
          }
    }
  return ! (fast == NULL || fast -> next == NULL);
}
int main()
{
    LIST* list = create_list();
    for(int i=10; i<=50;i+=10)
    {
        list_append(list,1);
    }
    cout<<"print the list:"<<endl;
    print(list);
    list_insert(list,5,10);
    cout<<" insert 5 after 10:"<<endl;
    print(list);
    list_del(list,30);
    cout<<" after delete 30:"<<endl;
    print(list);
    list_del(list,50);
    cout<<" after delete 50:"<<endl;
    print(list);
    list_end_append(list,3);
    list_end_append(list,4);
    list_end_append(list,5);
    cout<<" list end append:"<<endl;
    print(list);
    list_reverse(list);
    cout<<" reverse the list:"<<endl;
    print(list);
    cout<<" middle node of  the  list:"<<endl;
    cout<<middle_node(list)->data <<endl;
    destroy_list(list);
    return 0;
}