note description: "[ An EG_PARTICLE has a mass and a position. Plus three values dx, dy and dt which can be used to solve differential equations. ]" legal: "See notice at end of class." status: "See notice at end of class." author: "Benno Baumgartner" date: "$Date$" revision: "$Revision$" class EG_PARTICLE create make feature {NONE} -- Initialization make (ax, ay: INTEGER; a_mass: like mass) -- Make a particle with `a_mass' at position (`ax', `ay'). do internal_x := ax internal_y := ay mass := a_mass ensure set: x = ax and y = ay and mass = a_mass end feature -- Access x: INTEGER -- x position of particle. do Result := internal_x end y: INTEGER -- y position of particle. do Result := internal_y end mass: DOUBLE -- The mass of the particle. dx: DOUBLE -- Delta to x direction. dy: DOUBLE -- Delta to y direction. dt: DOUBLE -- Delta time. feature -- Element change set_delta (a_dx, a_dy: DOUBLE) -- Set `dx' to `a_dx' and `dy' to `a_dy' do dx := a_dx dy := a_dy ensure set: dx = a_dx and dy = a_dy end set_dt (a_dt: DOUBLE) -- Set `dt' to `a_dt' do dt := a_dt ensure set: dt = a_dt end feature {NONE} -- Implementation internal_x: INTEGER -- internal `x' position. internal_y: INTEGER; -- internal `y' position. note copyright: "Copyright (c) 1984-2010, Eiffel Software and others" license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)" source: "[ Eiffel Software 5949 Hollister Ave., Goleta, CA 93117 USA Telephone 805-685-1006, Fax 805-685-6869 Website http://www.eiffel.com Customer support http://support.eiffel.com ]" end -- class EG_PARTICLE