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测控技术与仪器专业英语阅读翻译.docx

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测控技术与仪器专业英语阅读翻译篇一：测控技术与仪器专业英语翻译5.InheritanceInFigure9.7,theclassesSalesOrderCheclcPmtandSalesOrderCreditPmtarecalledsubclassesofSalesOrder.TheclassSalesOrderiscalledthesuperclassofSalesOrderCheckPmtandSalesOrderCreditPmt.Therelationshipbetweenaclassanditssubclass(orsuperclass)iscalledgeneralizationorspecialization.Subclassesinheritattributesandoperationsfromtheirclass.Asubclasshasitsownadditionalattributesandoperations.Forexample,theclassSalesOrderCreditPmtinheritstheattributesorderNo,orderDate,deliveryDate,andorderTermsandthemethodscalcTotalandchangeDelivDate.Inthiscase,theclassSalesOrderisthegeneralizedclass,andSalesOrderCheckPrmtandSalesOrderCreditPrmtarethespecializedclasses.6.PolymorphismEarlieritwasmentionedthataDVRandaDVDplayerthatrespondsimilarlybutdifferentlytothesamemessagearepolymorphic.Polymorphismmeans"havingmanyforms".InthecontextofOQSAD,polymorphismmeansthatthesamemessagecaninvokesimilarbutdifferentbehavior.Thus,amessagethatinvokestheoperationcalcTotalQofa:SalesOrderobjectwillresultinthesalesordertotalcalculation;amessagethatinvokestheoperationcalcTotaIQofaPurchaseOrderobjectwillresultinapurchaseordertotalcalculation.Theimplementationoftheoperationsintherespectiveclasseswillbedifferent.FoundationsoftheobjectmodelStructureddesignmethodsevolvedtoguidedeveloperswhoweretryingtobuildcomplexsystemsusingalgorithmsastheirfundamentalbuildingblocks.Similarly,object-orienteddesignmethodshaveevolvedtohelpdevelopersexploittheexpressivepowerofobject-basedandobject-orientedprogramminglanguages,usingtheclassandobjectasbasicbuildingblocks.Foundationsoftheobjectmodel.Actually,theobjectmodelhasbeeninfluencedbyanumberoffactors,notjustobject-orientedprogramming.Theobjectmodelhasproventobeaunifyingconceptincomputerscience,applicablenotjusttoprogramminglanguagesbutalsotothedesignofuserinterfaces,databases,andevencomputerarchitectures.Thereasonforthiswidespreadappealissimplythatanobjectorientationhelpsustocopewiththecomplexityinherentinmanydifferentkindsofsystems.5。继承在图9.7中，