300 project

/******************************************************************************

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                Code, Compile, Run and Debug C program online.
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*******************************************************************************/

#include <stdio.h>
struct Node
{
    void* key;
    struct Node* next;
    struct Node* pre;
};

struct List
{
    struct Node* end;
    struct Node* current;
    struct Node* start;
    int start_index;
    int end_index;
    int current_index;
};
struct Node arr2[100];
struct List arr1[5];
int head_free_index=0;
int node_free_index=0;;
struct List* ListCreate()
{
   struct List* ret;
   if(head_free_index+1>=5 || node_free_index+1>=100)
    return NULL;
    arr2[node_free_index].next=NULL;
   arr2[node_free_index].pre=NULL;
   arr2[node_free_index].key=NULL;
   arr1[head_free_index].start=&arr2[node_free_index];
   arr1[head_free_index].end=&arr2[node_free_index];
   arr1[head_free_index].current=&arr2[node_free_index];
   arr1[head_free_index].start_index=head_free_index;
   arr1[head_free_index].end_index=head_free_index;
   arr1[head_free_index].current_index=head_free_index;
   ret=&arr1[head_free_index];
   head_free_index++;
   node_free_index++;
  return ret;
}
int ListCount(struct List A)
{

    struct Node* temp=A.start;
    int count=1;
    while(temp->next!=NULL)
    {
       count++;
    temp=temp->next;

    }
    return count;
}
void* ListFirst(struct List A)
{
    A.current=A.start;
    return A.start;
}
void* ListLast(struct List A)
{
    A.current=A.end;
    return A.end;
}
void* ListNext(struct List A)
{
    if(A.current->next==NULL)
     return NULL;
    A.current=A.current->next;
    return A.current;
}
void* ListPrev(struct List A)
{
    if(A.current->pre==NULL)
        return NULL;
    A.current=A.current->pre;
    return A.current;
}
void* ListCurr(struct List A)
{
    return A.current;
}
int ListAdd(struct List A, void* item )
{
    struct Node newNode;
    newNode.key=item;
    if(node_free_index>=100)
    return -1;
    if(A.current==NULL && A.current->next!=NULL)
    {
        newNode.next=A.start;
        A.start->pre=&newNode;
        newNode.pre=NULL;
        A.start=&newNode;
        A.current=&newNode;

    }
    if(A.current==NULL && A.current->pre!=NULL)
    {
        newNode.pre=A.end;
        A.end->next=&newNode;
        newNode.next=NULL;
        A.end=&newNode;
        A.current=&newNode;
    }
    else
    {
        newNode.next=A.current->next;
        A.current->next=&newNode;
        newNode.pre=A.current;
        newNode.next->pre=&newNode;
    }
    for(int i=node_free_index;i>A.current_index;i--)
    {
        arr2[i].key=arr2[i-1].key;
        arr2[i].next=arr2[i-1].next;
        arr2[i].pre=arr2[i-1].pre;
    }
    for(int i=0;i<head_free_index;i++)
    {
        if(i!=0)
        arr1[i].start=arr1[i].start->next;
        arr1[i].end=arr1[i].end->next;
        arr1[i].current=arr1[i].current->next;
    }

}
int main()
{
    arr1[0]=*ListCreate();
    struct List C;
    C.start=arr1[0].start;
    C.end=arr1[0].end;
    C.current=arr1[0].current;

    int a = ListCount(C);
    printf("%d", a);
    return 0;
}