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ID:51669184
大小:242.50 KB
页数:32页
时间:2020-03-28
《计算机科学导论-Software Engineering.ppt》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、Chapter7SoftwareEngineeringObjectivesUnderstandthesoftwarelifecycle.Describethedevelopmentprocessmodels..Understandtheconceptofmodularityinsoftwareengineering.Understandtheimportanceofqualityinsoftwareengineering.Understandtheroleofdocumentationinsoftwareenginee
2、ring.SystemlifecycleSoftware,likemanyotherproducts,goesthroughacycleofrepeatingphases.SystemdevelopmentphasesThedevelopmentprocessinthesoftwarelifecycleinvolves4phases.AnalysisDefinetheuser(genericorspecific?)Definetheneeds(expectations)DefinetherequirementsDefi
3、nethemethods(tomeetrequirements)DesignphaseThedesignphasedefineshowthesystemwillaccomplishwhatwasdefinedintheanalysisphase.ModularityToolsStructurechartUMLImplementationphaseToolsFlowchartPseudocodeCodingTestingphaseBlackboxtesingBlackboxtestplansaredevelopedbyl
4、ookingonlyattherequirementsstatement.WhiteboxtestingWhiteboxtestingistheresponsibilityoftheprogrammer,whoknowsexactlywhatisgoingoninsidetheprogram.DevelopmentprocessmodelsWaterfallmodel:asequentialsoftwaredevelopmentprocess,inwhichprogressisseenasflowingsteadily
5、downwards(likeawaterfall)throughthephasesofConception,Initiation,Analysis,Design,Construction,TestingandMaintenance.DevelopmentprocessmodelsIntheincrementalmodel,theprocessisdevelopedinaseriesofsteps.Firstcompleteasimplifiedversionofthewholepackage.Graduallyaddm
6、oredetails.ModularityModularitymeansbreakingalargeprojectintosmallerpartsthatcanbeunderstoodandhandledeasily.ToolsStructurechartClassdiagramUnifiedModelingLanguage(UML)Modularity-couplingCouplingisameasureofhowtightlytwomodulesareboundtoeachother.Loosecouplingis
7、moredesirable,because:IndependentfunctionsaremoreresuableLesslikelytocauseproblemsMaintenancemodificationsareeasierModularity-couplingDatacoupling:passesonlytheminimumrequireddatafromthecallingfunctiontothecalledfunction.Mostdesirable.Stampcoupling:whentheparame
8、tersarecompositeobjectssuchasarrays.Controlcoupling:passesflagstodirectthecontrolflowofafunction.Globalcoupling:usesglobalvariables.Shouldneverbeused.Contentcoupling:
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