#include <stdio.h>
#include <stdlib.h>

typedef struct{
    int *plist;
    int size;
    int len;
}list;

void InitList(list *l,int size);
void Distroy(list *l);
void ClearList(list *l);
int  ListEmpty(list *l);
int  ListLength(list *l);
int  GetElem(list *l,int i,int *elem);
int  LocateElem(list *l,int *elem);
int  PriorElem(list *l,int *currentElem,int *preElem);
int  NextElem(list *l,int *currentElem,int *NextElem);
int  ListInsert(list *l,int i,int *elem);
int  ListDelete(list *l,int i,int *elem);
void ListTraverse(list *l);

void InitList(list *l,int size)
{
    l->size=size;
    l->plist=(int *)malloc(sizeof(list)*size);
    l->len=0;
}
void Distroy(list *l)
{
    free(l->plist);
    l->plist=NULL;
}
void ClearList(list *l)
{
    l->len=0;
}
int  ListEmpty(list *l)
{
    if (l->len)
        return 0;
    return 1;
}
int  ListLength(list *l)
{
    return l->len;
}

int  GetElem(list *l,int i,int *elem)
{
    if(i<0||i>=l->size)
        return 1;
    *elem=l->plist[i];
    return 0;
}
int  LocateElem(list *l,int *elem)
{
    int i;
    for (i=0;i<l->len;i++)
    {
        if(l->plist[i]==*elem)
        {
            return i;
        }
    }
    return -1;
}
int  PriorElem(list *l,int *currentElem,int *preElem)
{
    int temp=LocateElem(l,currentElem);
    if(temp==-1)
    {
        return -1;
    }
    else 
    {
        if(temp==0)
        {
            return -1;
        }
        else
        {
            *preElem=l->plist[--temp];
            return 0;
        }
    }
    
}
int  NextElem(list *l,int *currentElem,int *NextElem)
{
    int temp=LocateElem(l,currentElem);
    if(temp==-1)
    {
        return -1;
    }
    else
    {
        if(temp==l->size-1)
        {
            return -1;
        }
        else
        {
            *NextElem=l->plist[++temp];
            return 0;
        }
    }
}

int  ListInsert(list *l,int i,int *elem)
{
    int k;
    if (i<0||i>l->len)
    {
        return -1;
    }
    //l->plist=(int *)realloc(l->plist,(l->size+1)*sizeof(int));
    for (k=l->len-1;k>=i;k--)
    {
        l->plist[k+1]=l->plist[k];
    }
    l->plist[i]=*elem;
    l->len++;
    return 0;
}
int  ListDelete(list *l,int i,int *elem)
{
    int k;
    if (i<0||i>=l->len)
    {
        return -1;
    }
    *elem=l->plist[i];
    for (k=i+1;k<l->len;k++)
    {
        l->plist[k-1]=l->plist[k];
    }
    //l->plist=(int *)realloc(l->plist,(l->size-1)*sizeof(int));
    l->len--;
    return 0;
}

void ListTraverse(list *l)
{
    int i;
    for (i=0;i<l->len;i++)
    {
        printf("%d\n",l->plist[i]);
    }
}