Expert problem solving strategies for program comprehension

Program comprehension is a complex problem solving process. We report on an experiment that studies expert programmers’ comprehension behavior in the context of modifying a complex PASCAL program. Our data suggests that program comprehension is best understood as a goal– oriented, hypotheses-driven problem–solving process. Programmers follow a pragmatic as-needed rather than a systematic strategy, they restrict their understanding to those parts of a program they find relevant for a given task, and they use bottom-up comprehension only for directly relevant code and in cases of missing, insufficient, or failing hypotheses. These findings have important consequences for the design of cognitively adequate computer–aided software engineering tools.