《面向对象特征》ppt课件

《《面向对象特征》ppt课件》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、第6讲面向对象特征(2)武汉大学国际软件学院1接口是对abstract类的进一步扩展接口中的方法都是未实现的(类似于抽象方法)，目的是在实现接口的类之间建立一种协议接口中的变量都是常量定义一个类符合某个或一组接口,利用implements6.1接口(interface)Aninterfaceisanamedcollectionofmethoddefinitions(withoutimplementations).Aninterfacecanalsodeclareconstants.[public]interface接口名{成员变量;方法声明;}class类名im

2、plements接口1,接口2……{………}2接口名修饰public:无任何访问限制无修饰:仅限于本包中接口变量默认都是“publicstaticfinal”publicinterfaceMonths{intJANUARY=1,FEBRUARY=2,MARCH=3,APRIL=4,MAY=5,JUNE=6,JULY=7,AUGUST=8,SEPTEMBER=9,OCTOBER=10,NOVEMBER=11,DECEMBER=12;}6.1.1接口名修饰36.1.2接口方法接口方法无修饰但在实现接口方法的类中，修饰符为publicinterfaceFigure{d

3、oublehalf=0.5,pi=3.14159;voidparameter();voidarea();}classTriangleimplementsFigure{doubleb,h;Triangle(doubleu,doublev){b=u;h=v;}publicvoidparameter(){System.out.println(b+““+h);}publicvoidarea(){System.out.println(half*h*b);}}classCircleimplementsFigure{doublex,y,r;Circle(doubleu,dou

4、blev,doublem){x=u;y=v;r=m;}publicvoidparameter(){System.out.println(x+““+y+““+r);}publicvoidarea(){System.out.println(pi*r*r);}}Trianglet=newTriangle(2,3);Circlec=newCircle(4,5,6);Figure[]f={t,c};for(inti=0;i

5、多个接口合并为一个新的接口interfaceDC{intadd(intx,inty);}interfaceDBextendsDC{intsub(intx,inty);}interfaceDAextendsDB{intmul(intx,inty);}interfaceDY{intdiv(intx,inty);}interfaceDXextendsDY{intmod(intx,inty);}classDDimplementsDA,DX{publicintadd(intx,inty){returnx+y;}publicintsub(intx,inty){returnx

6、-y;}publicintmul(intx,inty){returnx*y;}publicintdiv(intx,inty){returnx/y;}publicintmod(intx,inty){returnx%y;}}56.1.4接口多重继承利用接口实现多重继承(Multipleinheritance)classextends父类implements接口interfaceCanFight{voidfight();}interfaceCanSwim{voidswim();}interfaceCanFly{voidfly();}classActionCharact

7、er{publicvoidfight(){}}classHeroextendsActionCharacterimplementsCanFight,CanSwim,CanFly{publicvoidswim(){}publicvoidfly(){}}66.1.5接口合并时的命名冲突interfaceA1{voidf();}interfaceA2{intf(inti);}interfaceA3{intf();}classC{publicintf(){return4;}}classC1implmentsA1,A2{publicvoidf(){}publicintf(i

8、nti){return5