// FILE: bag3.h 
// CLASS PROVIDED: bag (part of the namespace main_savitch_5)
//
// TYPEDEFS for the bag class:
//   bag::value_type
//     is the data type of the items in the bag. It may be any 
//     of the C++ built-in types (int, char, etc.), or a class with a default
//     constructor, a copy constructor, an assignment
//     operator, and a test for equality (x == y).
//
//   bag::size_type
//     is the data type of any variable that keeps track of how many items are
//     in a bag
//
// CONSTRUCTOR for the bag class:
//   bag( )
//     Postcondition: The bag is empty.
//
// MODIFICATION MEMBER FUNCTIONS for the bag class:
//   size_type erase(const value_type& target)
//     Postcondition: All copies of target have been removed from the bag.
//     The return value is the number of copies removed (which could be zero).
//
//   bool erase_one(const value_type& target)
//     Postcondition: If target was in the bag, then one copy of target has
//     been removed from the bag; otherwise the bag is unchanged. A true
//     return value indicates that one copy was removed; false indicates that
//     nothing was removed.
//
//   void insert(const value_type& entry) 
//     Postcondition: A new copy of entry has been inserted into the bag.
//
//   void operator +=(const bag& addend) 
//     Postcondition: Each item in addend has been added to this bag.
//
// CONSTANT MEMBER FUNCTIONS for the bag class:
//   size_type size( ) const 
//     Postcondition: Return value is the total number of items in the bag.
//
//   size_type count(const value_type& target) const 
//     Postcondition: Return value is number of times target is in the bag.
//
//   value_type grab( ) const 
//     Precondition: size( ) > 0.
//     Postcondition: The return value is a randomly selected item from the bag.
// 
// NONMEMBER FUNCTIONS for the bag class:
//   bag operator +(const bag& b1, const bag& b2) 
//     Postcondition: The bag returned is the union of b1 and b2.
//
// VALUE SEMANTICS for the bag class:
//    Assignments and the copy constructor may be used with bag objects.
//
// DYNAMIC MEMORY USAGE by the bag: 
//   If there is insufficient dynamic memory, then the following functions throw
//   bad_alloc: The constructors, insert, operator +=, operator +, and the
//   assignment operator.

#ifndef MAIN_SAVITCH_BAG3_H
#define MAIN_SAVITCH_BAG3_H
#include <cstdlib>   // Provides size_t and NULL
#include "node1.h"   // Provides node class
namespace main_savitch_5
{
    class bag
    {
    public:
        // TYPEDEFS
        typedef std::size_t size_type;
        typedef node::value_type value_type;
        // CONSTRUCTORS and DESTRUCTOR
        bag( );
        bag(const bag& source);
	~bag( );
        // MODIFICATION MEMBER FUNCTIONS
        size_type erase(const value_type& target);
        bool erase_one(const value_type& target);
        void insert(const value_type& entry);
        void operator +=(const bag& addend);
        void operator =(const bag& source);
        // CONSTANT MEMBER FUNCTIONS
        size_type size( ) const { return many_nodes; }
        size_type count(const value_type& target) const;
        value_type grab( ) const;
    private:
        node *head_ptr;       // List head pointer 
        size_type many_nodes; // Number of nodes on the list
    };

    // NONMEMBER FUNCTIONS for the bag class:    
    bag operator +(const bag& b1, const bag& b2);
}
#endif