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From: rj@tcom.stc.co.uk (Ray Jones)
Newsgroups: comp.software-eng
Subject: Design Methods and Flow charts
Message-ID: <1440@bute.tcom.stc.co.uk>
Date: 20 Jul 88 11:06:16 GMT
Reply-To: Ray Jones <rj@stc.UUCP>
Organization: STC Telecoms, London N11 1HB.
Lines: 43


    I've just been browsing through the sw-eng digest and have come across
    discussions about software design methods, that, being a newcomer to
    the net, I have previously missed. Sorry if this is a little late
    but... 
    
    I am astounded that I have not heard more talk about formal
    methodologies that we in the UK have imported (I think) from the USA.
    Haven't (most of you) heard of Ed Yourdon or Michael Jackson (no, no,
    the *other* one) and their respective methodologies. I was introduced
    to the Yourdon method for real-time systems design, a while ago, only
    to find that I've been using the same tools as he suggests for years
    (i.e. data flow diagrams, state transition diagrams and structure
    charts) but in a less formal way. Yourdon has formalised a structured
    method that good analysts and designers would, I think, find very
    familiar. If you want to know more about this, check out the books
    published by the Yourdon Press (available from Prentice-Hall, in the
    UK) by authors such as Ward and Mellor, DeMarco, Yourdon and others.
    Don't buy them yourself, though, they cost a fortune (in the UK at
    least). 
    
    Changing the subject slightly...
                                                               
    One tool that I have not used in years (don't you dare!) is the flow
    diagram. The traditional flow diagram is ok for describing simple
    systems that have already been designed, but as a design tool they can
    be a menace. They encourage non-structured programming and the
    indiscriminent use of gotos (let's not get into a discussion about
    gotos though, please). Flow diagrams do not, directly, support the
    constructs used in modern languages, i.e. while loops, case statements
    functions, etc., and are more suitable to the construction of programs
    in Fortran IV (Oh, God those were the days...) than languages such as C
    and Pascal (and even F77). I find that a high level pseudo-code or
    structured English, is a more suitable method of describing the
    procedural aspects of a system. 
    
    Enough of that, anyone know about any good books on object orientated
    design ? 
    
    Keep on hacking you guys (snigger, snigger)
    
    Ray