// FILE: stack3.template
// TEMPLATE CLASS IMPLEMENTED: stack<Item> (see stack3.h for documentation)
// This file is included in the header file, and not compiled separately.
// INVARIANT for the stack class:
//   1. The number of items in the stack is in the member variable used.
//   2. The actual items of the stack are stored in a partially-filled
//      array data[0]..data[used-1]. The stack elements appear from the
//      bottom (at data[0]) to the top (at data[used-1]).

#include <cassert>  // Provides assert

namespace main_savitch_7A
{
    template <class Item>
    const typename stack<Item>::size_type stack<Item>::CAPACITY;
    
    template <class Item>
    void stack<Item>::push(const Item& entry)
    // Library facilities used: cassert
    {
        assert(size( ) < CAPACITY);
        data[used] = entry;
        ++used;
    }
    
    template <class Item>
    void stack<Item>::pop( )
    // Library facilities used: cassert
    {
        assert(!empty( ));
        --used;
    }

    template <class Item>
    Item& stack<Item>::top( )
    // Library facilities used: cassert
    {
        assert(!empty( ));
        return data[used-1];
    }

    template <class Item>
    const Item& stack<Item>::top( ) const
    // Library facilities used: cassert
    {
        assert(!empty( ));
        return data[used-1];
    }
}