CodeHS 4.14 Polymorphism

Given this hierarchy of classes, which of these declarations are illegal?

Check all that apply.

• Shape foo = new Rectangle();

• Shape bar = new Square();

• Rectangle zim = new Square();

• Ellipse dib = new Shape();

• Ellipse gaz = new Circle();

What is late binding?

• The proper method is called at run-time

• The proper method is called at compile time

• The class is assigned a superclass

• A variable type is cast to another type

Assuming Rectangle and Square are both concrete classes, which version of getArea() will be executed at run-time?

• The version in Shape

• The version in Rectangle

• The version in Square

• Trick question: there will be a compiler error

Assuming Square is a subclass of Rectangle which is a subclass of Shape and all are concrete classes, which version of getArea() will be executed at run-time?

• The version in Shape

• The version in Rectangle

• The version in Square

• Trick question: there will be a compiler error

What is a hierarchy?

• Any group of objects ranked so that every one but the topmost is subordinate to a specified one above it

• A level or rank in an organization

• The bourgeoisie

• The person or organization in charge

When class Bar is based on class Foo, what do we call Foo?

• subclass

• superclass

• extends

• super

What does it mean to override a superclass method?

• A method in the subclass has the same signature as one in the superclass, and the subclass method is used

• A method in the subclass has the same signature as one in the superclass, and the superclass method is used

• An instance variable in the subclass has the same signature as one in the superclass, and the subclass instance variable is used

• A instance variable in the subclass has the same signature as one in the superclass, and the superclass instance variable is used

Which of these are advantages of using methods?

• code is easier to understand

• avoid writing repeated code

• make code reuseable

• conserve memory space

• flex on script kiddies

What is dynamic binding?

• Late binding

• A pullover stitch in knitting

• A protein the carries another molecule

• Putting a cover on a book.

Put these in the proper order

• Galileo Galileo Galileo Galileo Galileo Figaro

• Magnifico

• I see a little silhouetto of a man

• Scaramouche, Scaramouche, will you do the Fandango

• Thunderbolts and lightning, very very frightening me