From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: fac41,9a0ff0bffdf63657 X-Google-Attributes: gidfac41,public X-Google-Thread: f43e6,9a0ff0bffdf63657 X-Google-Attributes: gidf43e6,public X-Google-Thread: 1108a1,9a0ff0bffdf63657 X-Google-Attributes: gid1108a1,public X-Google-Thread: 103376,4b06f8f15f01a568 X-Google-Attributes: gid103376,public From: "Robert Martin" Subject: Re: Module size (was Re: Software landmines) Date: 1998/09/03 Message-ID: <6snlos$bh6$1@hirame.wwa.com>#1/1 X-Deja-AN: 387793720 References: <6rfra4$rul$1@nnrp1.dejanews.com> <35DBDD24.D003404D@calfp.co.uk> <6sbuod$fra$1@hirame.wwa.com> <904556531.666222@miso.it.uq.edu.au> <6sgror$je8$3@news.indigo.ie> <6sh3qn$9p2$1@hirame.wwa.com> <6simjo$jnh$1@hirame.wwa.com> <6sjk3p$4tc$1@hirame.wwa.com> <6skgn4$3gq$1@hirame.wwa.com> X-MimeOLE: Produced By Microsoft MimeOLE V4.72.2106.4 Organization: WorldWide Access - Midwestern Internet Services - www.wwa.com Newsgroups: comp.lang.eiffel,comp.object,comp.software-eng,comp.lang.ada Date: 1998-09-03T00:00:00+00:00 List-Id: Jeffrey C. Dege wrote in message ... >I've been trying to run various size metrics against a fairly large >(130kloc) C++ project we finished a year or so ago, with an eye to >improving our estimating techniques. Some of the results have been >hard to explain to my manager. > >He used to program for a living, but he's never done real work in an OO >language. When I tell him the project has 510 classes, with 2871 methods, >he nods his head wisely. But when I tell him that 965 of those methods >contain one line of code each, he starts to frown. He asks me if maybe >we're taking modularization a bit too far. When I tell him that we have >63 methods that contain zero lines of code, he wants to know why we >bothered to write them in the first place, if they don't do anything. > >I can't think of a short answer. They exist for the same reason that we put zeroes in numbers -- they are place holders. Metrics are interesting things. In the absence of a theory, they indicate nothing other than a measurement of something. Clearly your manager has a theory, or at least a hypothesis, that he is applying the metrics to. Just as clearly, that theory is inaccurate. What kind of theory might be appropriate nowadays? It would be interesting to establish a standard histogram for method sizes. That histogram might follow an exponential distribution with a mean of around 20-30 lines, and a deviation on the order of 10 or so. Interestingly, a method with zero lines would be within 3 deviations of the mean; but a method with 100 lines would be well beyond six deviations from the mean. Robert C. Martin | Design Consulting | Training courses offered: Object Mentor | rmartin@oma.com | Object Oriented Design 14619 N Somerset Cr | Tel: (800) 338-6716 | C++ Green Oaks IL 60048 | Fax: (847) 918-1023 | http://www.oma.com "One of the great commandments of science is: 'Mistrust arguments from authority.'" -- Carl Sagan