1. Match$each$of$the$three$relationships$on$the$left$to$one$terminology$on$the$right:$ HASCA$ Inheritance$ e.g.,$a$library$has$a$book$

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1 COSC121:ReviewExercisesonInheritanceandInterfaces 1. Matcheachofthethreerelationshipsonthelefttooneterminologyontheright: HASCA Inheritance e.g.,alibraryhasabook ISCA Aggregation e.g.,acarisavehicle USESCA Dependency e.g.,adogusesascanner 2. Whataresomeofthebenefitsofsoftwarereuse?Listatleastonethatrelatestothe organizationofyourprogram,andonethatrelatestothemaintenanceofyourprogram. 3. Whyaretheconstructormethodsinaparentclassnotinheritedbyachildclass? 4. Inthefollowingexample,listallthreeISCArelationshipsdefined: public class Mammal { } public class Bird extends Mammal { } public class Penguin extends Bird { } 5. WhatproblemarisesifmultipleinheritancewereallowedinJava?Giveanexampleto illustratethissituation. 6. Whatissomethingyoucandobyextendingaclassthatyoucannotdobyimportingit instead? 7. Whatistherootclassofeveryclasshierarchy? 8. SupposeyoudefinedaDogclassandcreatedtwoDogobjects.Whatcriteriashouldbe usedtodetermineifthetwodogobjectsareequalornot? 9. Ifyouweretodefinetheequal()methodfromQuestion8,inwhichclasswouldyou needtodefineit? 10. Definetheequal()methodyousuggestedinQuestion8.

2 COSC121:ReviewExercisesonInheritanceandInterfaces 11. Fillintheblanksusingthefollowingdiagram: a. ClassAisa ofclassc. b. ClassBisa ofclassc. c. ClassEisa ofclassa. d. ClassDisa ofclassb. e. ClassAisa ofclassd. 12. Drawtheinheritancediagramforthefollowingclasses:Reading,Newspaper,Novel, Textbook. 13. BasedonyourdiagramfromQuestion12,whichclass(es)maymakesensetobedefined asanabstractclass?why? 14. Whenwedefineamethodinsideaclass,howisanabstractmethoddifferentfromanonC abstractmethod? 15. Listthedifferencesbetweenoverridingandoverloading. Overriding: Overloading: 16. Listthedifferencesbetweeninheritanceandinterfaces. Inheritance: Interfaces:

3 COSC121:ReviewExercisesonInheritanceandInterfaces 17. Listthedifferencesbetweenabstractclassesandinterfaces. Abstractclasses: Interfaces: 18. Trueorfalse? a. ImplementinginterfacesisgoodobjectCorientedprogrammingpractice. b. Anyclasscanextendfromanyotherclass. c. Aparentclassisthesameasasuperclass,andachildclassisthesameasa subclass. d. Achildclassmaydefineamethodwiththesamenameasamethodintheparent class. e. Achildclasscanoverridetheconstructoroftheparentclass. f. Achildclasscannotoverrideafinalmethodoftheparentclass. g. Itisconsideredpoordesignwhenachildclassoverridesamethodfromtheparent class. h. Achildclassmaydefineanattributewiththesamenameasanattributeinthe parentclass. i. Toreferenceaparentmethod,thechildclasscanusesuper()ifitisthe constructormethoditwantstocall,orsuper.methodname()ifitisanyother methoditwantstocall. j. Toreferenceaparentattribute,thechildclasscanusesuper.attributeName directly. k. Overloadingisthesameasoverriding. l. ClassesYandZarechildrenofX,andclassesAandBarechildrenofY.IfA,B,Y, andzallhavethesameattributevar1,thenvar1shouldbedeclaredinxand inheritedintoy,z,a,andb. m. Aprivatemethodcannotbemodifiedbyasubclass.SoifIwantthismethodtobe modifiablebysubclasses,imustchangeitsvisibilitytoprotected. n. Allmethodsinanabstractclassmustbeabstract. o. Anabstractmethodcanbedefinedasfinal. p. Anabstractmethodcannotbedefinedasstatic. q. Anabstractmethodmustbehavepublicvisibility. r. Abstractmethodsareusedtodefineclassesthathavenoconstructors. s. Aclassthatinheritsfromanabstractclassmustdefinealltheinheritedabstract methods. t. Aninterfaceisaspecialtypeofclass. u. Aclasscanimplementasmanyinterfacesasitwants.

4 COSC121:ReviewExercisesonInheritanceandInterfaces v. Allmethodsinaninterfacemustbeabstract. w. Aninterfacedoesnothaveanyattributes. x. Justlikeanabstractclass,aninterfacecannotbeinstantiated. y. Aclassthatimplementsaninterfacemustdefinealltheimplementedabstract methods. z. Allthemethodsinaninterfacemustbepublic. aa. Interfacescannotbeextended. bb. ThemethodcompareTo()isaninheritedmethodavailablefromthe Comparableclass. cc. AnyclasscandefineitsowncompareTo()methodbyimplementingthe Comparableinterface.Inthatcase,thedefinitionmustfollowthesamesignature asdictatedbythecomparableinterface. dd. Usinganinterfaceisabetterchoicethanusinganabstractclasswhenyouwant otherclassestoconformtoastandardsetofmethodprotocols. ee. Usinganabstractclassisabetterchoicewhenyouwantotherclassestohavesome defaultbehavior. 19. Whenwefirstintroduceshapestochildren,therearetypicallythreeshapeswetellthem about:square,circle,andtriangle.fromthesebasicshapes,othershapesarederived. Now,considertheclassesCircleandOvalthatsharecommonattributesandmethods. Wouldyourelatethesetwoviaaninheritancerelationshiporaninterfacerelationship? Why? 20. Imagineagameinwhichplayerscanattackotherplayers gameelements,suchasboxes, mirrors,balloons,etc.eachtypeofgameelementbelongstoadifferentclass.forexample, thereisaboxclass,whereaseriesofboxobjectscanbecreated;thereisamirror class,etc.,thereisaballoonclass,etc. Whatthesegameelementshaveincommonisthattheyallhaveabreak()methodthat explainswhataplayerneedstodoinorderforthegameelementtobreak.theyalsoall haveaisbroken()methodthatreturnsabooleandependingonwhethertheelementis intactorbrokenatthetime. Shouldthegameelementclasses,Box,Mirror,Balloon,berelatedviainheritanceor interface?why? 21. ContinuingwithQuestion20.Supposebreak()andisBroken()areabstractmethods initiallydefinedinbreakable.assumingitonlyhasthesetwomethods,define Breakablefully.

5 COSC121:ReviewExercisesonInheritanceandInterfaces 22. ConsiderthesuperclassSquareandthesubclassRectangle.TheSquareclasshas attributesnumsidesandlength,aswellasthefollowingmethods: calcperimeter(),whichreturnsadoublebasedonthestandarddefinitionofthe perimeterofasquare calcarea(),whichreturnsadoublebasedonthestandarddefinitionoftheareaof asquare isbiggerthan(),whichreturnsabooleanthatindicatesiftheobjectitselfisbigger inareathananinputsquareobject IfyouhadtodefinetheRectangleclass: a. Whatattributeswillithave? b. Whatmethodswillithave? c. Whatwillbethevisibilityforeach? d. Whichinheritedmethodwillyouoverride? Practicebydefiningbothclassesfully.