#ifndef LAB3LIST_H
#define LAB3LIST_H

#include <iostream>

using namespace std;

// What type our list is holding.  Most elegantly this would be
// done using templates, but for the purposes of this exercise that
// is slightly overkill and just tends to create such nasty error
// messages that I won't subject you all to that.
typedef int val_t;

/*****************************************************************
 * Predeclarations
 *****************************************************************/

// Predeclare that we will be defining a class ADTList
class ADTList;

/*****************************************************************
 * Interfaces
 *****************************************************************/

// The interface for the Abstract Data Type List.  
class ADTList
{
 public:
  virtual ~ADTList() { }

  // Insert val in position pos.  Pos = 0 implies "insert at head",
  // pos = size() implies "insert at tail"
  virtual void insert(val_t val, unsigned int pos) = 0;

  // Remove the element in position pos
  virtual void remove(unsigned int pos) = 0;

  // Return the element in position pos
  virtual val_t retrieve(unsigned int pos) = 0;
  
  // Is there anything in this list?
  virtual bool isEmpty() = 0;

  // How much is there in this list?
  virtual unsigned int size() = 0;

};


#endif // LAB3LIST_H