Size Estimation for C Programs with Different Applications

Cost estimation is an important aspect of the management of software development projects. Most cost estimation models require an estimate of the size of the program to be developed. Accurate size estimation is thus critically important. Earlier work has shown that weighted counts of conceptually unique variables (where each variable is weighted by the number of functions in which it is referenced) are good predictors of the final size of Pascal and C programs. Simple equations using only that information give acceptable accuracy, even across a range of sizes and applications. For Pascal programs, the accuracy is acceptable by the end of high level design; for C programs, it is acceptable by the end of detailed design. In this study, C programs are classified by application, instead of being treated as a single class. Different estimation equations are then used for programs in each class. Overall estimation accuracy improves at each stage of design. A broad classification scheme is sufficient to give estimates of acceptable accuracy by the completion of high level design. Keyword Codes: D.2.8; K.6.1.