//This is the file sale.cpp.
//This is the implementation for the class Sale.
//The interface for the class Sale is in the file sale.h.

#include <iostream>
#include "sale.h"
using std::cout;

namespace SavitchSale
{

    Sale::Sale( ) : price(0)
    {
        //Intentionally empty
    } 

    Sale::Sale(double thePrice)
    {
        if (thePrice >= 0)
            price = thePrice;
        else
        {
            cout << "Error: Cannot have a negative price!\n";
            exit(1);
        }
    }

    double Sale::bill( ) const
    {
        return price;
    }

    double Sale::getPrice( ) const
    {
        return price;
    }

    void Sale::setPrice(double newPrice)
    {
        if (newPrice >= 0)
            price = newPrice;
        else
        {
            cout << "Error: Cannot have a negative price!\n";
            exit(1);

        }
    }

    double Sale::savings(const Sale& other) const
    {
        return (bill( ) - other.bill( ));
    }

    bool operator < (const Sale& first, const Sale& second)
    {
        return (first.bill( ) < second.bill( ));
    }

}//SavitchSale