Verifiable program construction in a user-friendly style

The author presents a method for formal program development, designed specifically for use at an introductory level. It formalizes stepwise refinement in a natural way by regarding specifications as unimplemented program components. A graphical notation is used for specifications and their refinement rules, which supports this approach. The method places specifications and programs within the same semantic framework and gives the same meaning to the standard compositional operators (sequence, selection, and repetition) when applied to either.<<ETX>>