**CS1021 Software Development II** Lecture Videos Winter 2018-2019 Week 3 Lecture 1 # Introduction [download](lectures/1021-3-1a.mp4)  # Abstract Classes/Methods Review [download](lectures/1021-3-1b.mp4)  # Reference Casting Review [download](lectures/1021-3-1c.mp4)  # Visibility Review [download](lectures/1021-3-1d.mp4)  # Interfaces [download](lectures/1021-3-1e.mp4)