#include <stdio.h>
#include <malloc.h>
#include "LinkList.h"

typedef void LinkList;
typedef struct _tag_LinkListNode LinkListNode;


typedef struct _tag_LinkList
{
    LinkListNode header;                //线性表首地址也即表头
    int length;                         //线性表长度也即表长
} TLinkList;

LinkList* LinkList_Create() // O(1)
{
    TLinkList* ret = (TLinkList*)malloc(sizeof(TLinkList));
   
    if( ret != NULL )
    {
        ret->length = 0;                //当前数组长度置0
        ret->header.next = NULL;        //头指针的next为空
    }
   
    return ret;
}

void LinkList_Destroy(LinkList* list) // O(1)
{
    free(list);
}

void LinkList_Clear(LinkList* list) // O(1)
{
    TLinkList* sList = (TLinkList*)list;
   
    if( sList != NULL )
    {
        sList->length = 0;                          
        sList->header.next = NULL;
    }
}

int LinkList_Length(LinkList* list) // O(1)
{
    TLinkList* sList = (TLinkList*)list;
    int ret = -1;                       
   
    if( sList != NULL )
    {
        ret = sList->length;
    }
   
    return ret;
}

int LinkList_Insert(LinkList* list, LinkListNode* node, int pos) // O(n)
{
    TLinkList* sList = (TLinkList*)list;
    int ret = (sList != NULL) && (pos >= 0) && (node != NULL);
    int i = 0;
   
    if( ret )
    {
        LinkListNode* current = (LinkListNode*)sList;                  //  问题一 ：此处强制类型转换将TLinkList*强制转换为LinkListNode*
        
        for(i=0; (i<pos) && (current->next != NULL); i++)
        {
            current = current->next;
        }
        
        node->next = current->next;
        current->next = node;
        
        sList->length++;
    }
   
    return ret;
}

LinkListNode* LinkList_Get(LinkList* list, int pos) // O(n)
{
    TLinkList* sList = (TLinkList*)list;
    LinkListNode* ret = NULL;
    int i = 0;
   
    if( (sList != NULL) && (0 <= pos) && (pos < sList->length) )
    {
        LinkListNode* current = (LinkListNode*)sList;
        
        for(i=0; i<pos; i++)
        {
            current = current->next;
        }
        
        ret = current->next;
    }
   
    return ret;
}

LinkListNode* LinkList_Delete(LinkList* list, int pos) // O(n)
{
    TLinkList* sList = (TLinkList*)list;
    LinkListNode* ret = NULL;
    int i = 0;
   
    if( (sList != NULL) && (0 <= pos) && (pos < sList->length) )
    {
        LinkListNode* current = (LinkListNode*)sList;
        
        for(i=0; i<pos; i++)
        {
            current = current->next;
        }
        
        ret = current->next;
        current->next = ret->next;
        
        sList->length--;
    }
   
    return ret;
}

struct Value
{
    LinkListNode header;
    int v;
};

 //  ———————————————————以此往下为主函数部分——————————————————————

int main(int argc, char *argv[])           
{
    int i = 0;
    LinkList* list = LinkList_Create();
   
    struct Value v1;
    struct Value v2;
    struct Value v3;
    struct Value v4;
    struct Value v5;
   
    v1.v = 1;
    v2.v = 2;
    v3.v = 3;
    v4.v = 4;
    v5.v = 5;
   
    LinkList_Insert(list, (LinkListNode*)&v1, LinkList_Length(list));     //问题二：强制类型转换,将&v1又转换为LinkListNode*类型
    LinkList_Insert(list, (LinkListNode*)&v2, LinkList_Length(list));
    LinkList_Insert(list, (LinkListNode*)&v3, LinkList_Length(list));
    LinkList_Insert(list, (LinkListNode*)&v4, LinkList_Length(list));
    LinkList_Insert(list, (LinkListNode*)&v5, LinkList_Length(list));
   
    for(i=0; i<LinkList_Length(list); i++)
    {
        struct Value* pv = (struct Value*)LinkList_Get(list, i);
        
        printf("%d\n", pv->v);
    }
   
    while( LinkList_Length(list) > 0 )
    {
        struct Value* pv = (struct Value*)LinkList_Delete(list, 0);
        
        printf("%d\n", pv->v);
    }
   
    LinkList_Destroy(list);
   
    return 0;
}


//这是基本的动态链表操作，只不过表中用了很多的强制类型转换。。。楼主不明白的是为什么所定义的结构体根本不同，却可以通过强制转换实现这些操作？
//还有就是什么时候可以强制转换什么时候不可以~

给讲讲这些关于指针强制转换的原理吧！

your explain is so clear and detail , thank you so much!