List.h

const int maxlist=1000;
enum Error_code
{
    success,
    overflow,
    underflow,
    range_error
};
template <class List_entry>
class List
{
    public:
    //List();

    List():count(0)
    {}

    bool empty()
    {
    return count==0;
    }
    bool full()
    {
    return count==maxlist;
    }
    int size()
    {
        return count;
    }
    Error_code insert(int position, const List_entry &x)
    {
    if(full()) {
    return overflow;}
    if(position<0 || position>count)
    {
        return range_error;
    }
    for(int i=count-1;i>=position;i--)
    {
    entry[i+1]=entry[i];
    }
    entry[position]=x;
    count++;
    return success;
    }
    Error_code retrieve(int position, List_entry &x)const
    {
    if(empty()) return underflow;
    if(position<0 || position>count) return range_error;
    x=entry[position];
    return success;
    }

    Error_code replace(int position, const List_entry &x)
    {
    if(empty()) return underflow;
    if(position<0 || position>count) return range_error;
    entry[position]=x;
    return success;
    }
    Error_code remove(int position, List_entry &x)
    {
    if(empty()) return underflow;
    if(position>0 || position>=count) return range_error;
    for(int i=position;i<=count-1;i++)
    entry[i+1]=entry[i];
    count--;
    return success;
    }

    void traverse(void (*visit)(List_entry &x))//*visit is the pointer to function which performs operation on list
    {
    for(int i=0;i<count;i++)
    (*visit)(entry[i]);
    }

    protected:
    int count;
    List_entry entry[maxlist];
};