Search

This paper discusses the hierarchical properties of digraphs and proposes flowchart decomposition algorithms using these properties. The hierarchical structure discussed here is based on only the topological relation- skips between vertices and the inclusive relationship among sets of vertices. When the given flowchart represents the control flow of a computer program, this hierarchical structure also shows strong correspondence between these inclusive relationships and program modules. The proposed flowchart decomposition algorithm consists of one algorithm for detecting modules and another algorithm for further decomposing the detected modules. This paper focuses on the former algorithm. Because the hierarchical structure discussed in this paper corresponds to the traditional program modules (e.g., function or procedure) of most of the computer programming languages, the module-detection algorithm can be used not only for decomposing flowchart but for more general purposes, including module design. Two types of module-detection algorithm are discussed in this paper. One detects all modules, and the other detects a restricted subset of modules from the standpoint of flow-chart decomposition. We then demonstrate with a practical example that the latter algorithm is ten times faster than the former. [ABSTRACT FROM AUTHOR]