L_LIST.h

//******************************************
// Purpose: To define a singly-linked list.
// The list will dwell in the heap.
//******************************************
#pragma once


//******************************************
template<class TYPE>
class DIR_DATA  //dir_data = directed data
{
public:
    // data
    TYPE                its_data;
    DIR_DATA<TYPE>  *   its_next_p;
    
    DIR_DATA();
    DIR_DATA( const TYPE  & data, DIR_DATA<TYPE>  * next_p)
    {its_data = data; its_next_p=next_p;}
    DIR_DATA(const DIR_DATA<TYPE>  & source);       
};

// The class DIR_DATA, which will be used only by the class L_LIST,
// has only some of the four horsemen, only those that will be used
// by the class L_LIST. In particular, the assigner will not be used.
// Also, there is no need for an explicit destructor as 
// DIR_DATA never calls "new".

    
//******************************************
template<class TYPE>
class L_LIST
{   
private:
    DIR_DATA<TYPE>  *   its_first_p;
    DIR_DATA<TYPE>  *   its_last_p;
    USHORT              its_len;  // len = length
public:
    VOID clear();
    VOID copy(const L_LIST<TYPE>  &  prev_list);    
    L_LIST();
    L_LIST(  const  L_LIST<TYPE>  &  s );
    L_LIST<TYPE>  &  operator=( const L_LIST<TYPE>  & rhs);
    virtual ~L_LIST();

    DIR_DATA<TYPE>  *   get_first_p() const;
    DIR_DATA<TYPE>  *   get_last_p() const;
    const USHORT        get_len() const;    
    BOOLEAN  has_this( const TYPE  & target) const;
    TYPE  &   operator[] (USHORT loc) const;

    VOID    insert_first(const TYPE  & data);
    VOID    insert_last(const TYPE  & data);
    
    BOOLEAN     extract_first( TYPE  & data);
    BOOLEAN     extract_first();    
    BOOLEAN     extract_last();
    BOOLEAN     extract_target( const TYPE  & target);
    BOOLEAN     extract_target( DIR_DATA<TYPE>  * target_p);
    
    
};