继承是面向对象语言的重要特征之一继承是把已有类作为.ppt

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1、CHAPTER10Inheritance继承IntroductionAkeyfeatureofanobject-orientedlanguageininheritance.Inheritanceistheabilitytodefinenewclassesusingexistingclassesasabasis.Thenewclassinheritstheattributesandbehaviorsoftheclassesonwhichitisbased,anditcanalsohaveattributesandb

2、ehaviorsthatarespecifictoit.继承是面向对象语言的重要特征之一。继承是把已有类作为基类定义新的类。这个新的类继承了基类的属性和操作，而且还可以具有自己特定的属性和操作。Threerelationshipsarecommonlyusedinobject-orienteddesign:is-arelationshipsHierarchyrelationship.Itspecifiesthatoneabstractionisaspecializationofanother.has-arelat

3、ionshipsContainrelationship.Someobjectispartofanother.uses-arelationshipsOneobjectusesanotherobjectinsomeway.10.1OBJECT-ORIENTEDDESIGNUSINGINHERITANCEis-arelationshipsAB1B2C1C2C3BaseclassofB1andB2DerivedclassofABaseclassofC1,C2andC3DerivedclassofABaseclassof

4、C3DerivedclassofB1andB2MultipleinheritanceDerivedclassofB1has-arelationshipsclassA{…BDMi…FM};classB{…DM…FM};uses-arelationshipsclassA{…DM…FMj(B&…)};classB{…DM…FM};classDerivedClass:publicBaseClass{public://publicsection…private://privatesection…};10.3.1Declar

5、ingaderivedclassclassDerivedClass:publicBaseClass{public://publicsection…private://privatesection…};10.3.1DeclaringaderivedclassDerivedclassnameclassDerivedClass:publicBaseClass{public://publicsection…private://privatesection…};10.3.1DeclaringaderivedclassAcc

6、essspecifier(usuallypublic)classDerivedClass:publicBaseClass{public://publicsection…private://privatesection…};10.3.1DeclaringaderivedclassClassnameofbaseclassDeclarevehicleclassandderivedclasscar：classvehicle{public:voidinitialize(intin_wheels,floatin_weight

7、);intget_wheels();floatget_weight();floatget_loading();private:intwheels;floatweight;floatloading;}；classcar:publicvehicle{public:voidinitialize(intin_wheels,floatin_weight,intpeople=4);intpassengers();private:intpassenger_load;}；ExampleThesyntaxfortheconstru

8、ctorofderivedclassis10.3.2ImplementingaderivedclassDClass::DClass(Plist):BClass(Plist),DMbrList{//Bodyofderivedclassconstructor…}Thesyntaxfortheconstructorofderivedclassis10.3.2Implementi