Formal Transformations : Using SA and VDM as Di erent

Structured methods and formal methods for software development can supplement each other by eliminating each other's weak points. It is even better if an eeciently high level of integration can be achieved such that the products of each method can automatically be transformed into a product of the other method. In this paper a small case study is presented in which this principle is illustrated. It is shown how data ow diagrams (the main product of Structured Analysis) can automatically be translated into VDM speciications, in this way creating two diierent views for the analyst/designer on the system being developed: a graphical view (the DFD) and a textual view (the VDM speciication).