indexing
	description: "Demo calculator"
	project: "Project Goanna <http://sourceforge.net/projects/goanna>"
	library: "SOAP"
	date: "$Date$"
	revision: "$Revision$"
	author: "Glenn Maughan <glennmaughan@users.sourceforge.net>"
	copyright: "Copyright (c) 2001 Glenn Maughan and others"
	license: "Eiffel Forum License v2 (see forum.txt)."
	
class	CALCULATOR

feature -- Basic operations

	times (arg1, arg2: DOUBLE_REF): DOUBLE_REF is
			-- Multiply 'arg1' by 'arg2'
		require
			arg1_exists: arg1 /= Void
			arg2_exists: arg2 /= Void
		do
			Result := arg1 * arg2
		ensure
			multiplied: Result.item = (arg1 * arg2).item
		end
	
	divide (arg1, arg2: DOUBLE_REF): DOUBLE_REF is
			-- Divide 'arg1' by 'arg2'
		require
			arg1_exists: arg1 /= Void
			arg2_exists: arg2 /= Void
		do
			Result := arg1 / arg2
		ensure
			divided: Result.item = (arg1 / arg2).item
		end
	
	minus (arg1, arg2: DOUBLE_REF): DOUBLE_REF is
			-- Subtract 'arg2' from 'arg1'.
		require
			arg1_exists: arg1 /= Void
			arg2_exists: arg2 /= Void
		do
			Result := arg1 - arg2
		ensure
			subtracted: Result.item = (arg1 - arg2).item
		end
		
	plus (arg1, arg2: DOUBLE_REF): DOUBLE_REF is
			-- Add 'arg1' to 'arg2'
		require
			arg1_exists: arg1 /= Void
			arg2_exists: arg2 /= Void
		do
			Result := arg1 + arg2
		ensure
			added: Result.item = (arg1 + arg2).item
		end

end -- class CALCULATOR