// FILE: queue1.template
// TEMPLATE CLASS IMPLEMENTED: queue<Item> (see queue1.h for documentation)
// This file is included in the header file, and not compiled separately.
// INVARIANT for the queue class:
//   1. The number of items in the queue is in the member variable count;
//   2. For a non-empty queue, the items are stored in a circular array
//      beginning at data[front] and continuing through data[rear].
//      The array's total capacity of the array is CAPACITY.
//   3. For an empty array, rear is some valid index, and front is
//      always equal to next_index(rear).
//      

#include <cassert>  // Provides assert

namespace main_savitch_8B
{
    template <class Item>
    const typename queue<Item>::size_type queue<Item>::CAPACITY;
    
    template <class Item>
    queue<Item>::queue( )
    {
        count = 0;
        first = 0;
        last = CAPACITY - 1;
    }

    template <class Item>
    Item queue<Item>::front( ) const
    // Library facilities used: cassert
    {
        assert(!empty( ));
	return data[first];
    }

    template <class Item>
    void queue<Item>::pop( )
    // Library facilities used: cassert
    {
        assert(!empty( ));
        first = next_index(first);
        --count;    
    }
    
    template <class Item>
    void queue<Item>::push(const Item& entry)
    // Library facilities used: cassert
    {
        assert(size( ) < CAPACITY);
        last = next_index(last);
        data[last] = entry;
        ++count;
    }

}