Program complexity using Hierarchical Abstract Computers

A model of program complexity is introduced which combines structural control flow measures with data flow measures. This complexity measure is based upon the prime program decomposition of a program written for a Hierarchical Abstract Computer. It is shown that this measure is consistent with the ideas of information hiding and data abstraction. Because this measure is sensitive to the linear form of a program, it can be used to measure different concrete representations of the same algorithm, as in a structured and an unstructured version of the same program. Application of the measure as a model of system complexity is given for “upstream” processes (e.g. specification and design phases) where there is no source program to measure by other techniques.