Is disciplined programming transferable, and is it insightful?

This paper examines the disciplined programming methodology of EM Dijkstra which advocates the development of correctness proofs simultaneously with writing a program, (if not before) in the context of two problems which faced the authors recently. The paper applies the thought processes advocated by Dijkstra to these problems and indicates the insights that the authors gained from this. In both cases algorithms new to the authors were derived, and the properties of these are also examined. The paper should be interesting to those concerned with increasing the effectiveness of programming, for it demonstrates that the techniques advocated by Dijkstra are indeed transferable to other programmers, and that this transfer yields better insight into the activity we call programming.