Software design with invocation diagram

This paper describes a medium being developed for abstraction and expression of program structure. The medium is to be used to represent programs during the design process; It forms the basis for their implementation. The following point of view is adopted. Program design is an iterative, trial-and-error process, in which a basic solution to part of the problem is refined, added to, and modified into a complete solution. The final result should be well-structured in the sense described by Dijkstra (1) in order for the designer to understand the program sufficiently to be confident in its correctness.