stack2.template

// FILE: stack2.template
// TEMPLATE CLASS IMPLEMENTED: stack<Item> (see stack2.h for
// documentation)
// This file is included in the header file, and not compiled separately.
// INVARIANT for the stack class:
//   1. The items in the stack are stored in a linked list, with the top of the
//      stack stored at the head node, down to the bottom of the stack at the
//      final node.
//   2. The member variable top_ptr is the head pointer of the linked list.

#include <cassert>  // Provides assert
#include "node2.h"  // Node template class

namespace main_savitch_7B
{ template <class Item>
    stack<Item>::stack(const stack<Item>& source)
        // Library facilities used: node2.h
    { main_savitch_6B::node<Item> *tail_ptr;
        // Needed for argument of list_copy
        main_savitch_6B::list_copy(source.top_ptr, top_ptr, tail_ptr);
    }

    template <class Item>
    void stack<Item>::push(const Item& entry)
    // Library facilities used: node2.h
    {
        main_savitch_6B::list_head_insert(top_ptr, entry);
    }

    template <class Item>
    void stack<Item>::pop( )
    // Library facilities used: cassert, node2.h
    {  assert(!empty( ));
        main_savitch_6B::list_head_remove(top_ptr);
    }

    template <class Item>
    void stack<Item>::operator =(const stack<Item>& source)
    // Library facilities used: node2.h
    {    main_savitch_6B::node<Item> *tail_ptr; // Needed for argument of list_copy
        if (this == &source) // Handle self-assignment
            return;
        main_savitch_6B::list_clear(top_ptr);
        main_savitch_6B::list_copy(source.top_ptr, top_ptr, tail_ptr);
    }

    template <class Item>
    Item stack<Item>::top( ) const     // Library facilities used: cassert
    {  assert(!empty( ));
        return top_ptr->data( );
    }
}