// FILE: throttle.cxx
// CLASS IMPLEMENTED: throttle (See throttle.h for documentation.)

#include <cassert>     // Provides assert
#include "throttle.h"  // Provides the throttle class definition
using namespace std;   // Allows all Standard Library items to be used

namespace main_savitch_2A
{
    
    throttle::throttle( )
    {   // A simple on-off throttle
        top_position = 1;
        position = 0;
    }
    
    throttle::throttle(int size)
    // Library facilities used: cassert
    {
        assert(size > 0);
        top_position = size;
        position = 0;
    }
    
    void throttle::shift(int amount)
    {
	position += amount;

	if (position < 0)
	    position = 0;
	else if (position > top_position)
	    position = top_position;
    }

}