AP Computer Science 1.1 Inheritance, Abstraction, and Polymorphism

AP Computer Science 1.1 Inheritance, Abstraction, and Polymorphism. Which of the following are correct?

APAP Computer Science
AP Computer ScienceInheritance, Abstraction, and Polymorphism
Computer ScienceAP Computer Science
LanguageEnglish Language
Program AnalysisProgram correctness
Test PrepAP Computer Science

Transcript

00:22

problem states up arrows indicated inheritance relationship and we already

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know that inheritance is just a big fancy word for

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is a relationship No fast song is a song slow

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song is a song too and we can go step

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further and say power ballad is a slow song which

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is a song Well we could extend this even further

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by saying november rain is a power ballad november rain

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than inherits any and all of the fields methods and

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nested classes from power ballad which inherits from slow song

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which inherits from song for exam song would contain members

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that are relevant all songs and every subclass of song

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things like are this name instruments song blank and so

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on things that every song will have Well november rain

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would be extremely specific like emotional axl rose vocal which

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is something out every single half aside from simply knowing

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their relationship between classes It's also important to know how

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to properly declare and create a variable setting it all

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up typically goes like this class variable named equals new

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glass for supplies Yeah right left side of the equation

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declares a variable to refer to An object song a

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for example lets the compiler know that you're going to

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use a to refer to data of the variety song

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but that object doesn't actually yet exist On the other

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side of the equation we get down and dirty and

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actually a sign an object to that variable A new

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power ballad for example would be created with song a

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equals new power valid All right the question is asking

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us which of these three option for declaring in creating

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variables are correct starting with option one song a equals

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new power balance and that's what we just did a

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second ago and it works too and song be equals

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New slow jam Yeah perfectly good way of creating a

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slow jam Another good way would involve candles rose petals

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and a saxophone solo But this is a little quicker

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option One is good Option two is a little weird

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It has as creating a slow song and power valid

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and having them equal new song and slow song objects

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but that's just not gonna fly the left side of

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the equation declares variables name and its class and the

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right side actually creates the object Option two is trying

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to declare a variable of the type that's a subclass

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of the actual object or creating that's like declaring that

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you're going to be dracula for halloween But he actually

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dress up some generic monster The option to option three

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works like option one declaring variables and b to be

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songs and then creates new fast song and slow song

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objects So yeah three work with options One of three

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working and to being wrong That makes the our answer