Ruby Classes and Methods Quiz

Questions and Answers

What is an implicit return?

A method that never returns a value

A return that explicitly uses the keyword 'return'

A type of error in Ruby

A return that does not explicitly use the keyword 'return' (correct)

What is a class?

Classes are the basic template from which object instances are created.

When should you use a class?

When you have several methods that could be grouped together to do the smallest possible thing or when you need to construct similar objects.

How do you create a class in your script file?

Start with the keyword 'class', give the class a name, and close with the keyword 'end'. Signup and view all the answers

What is an instance of a class?

An object created from the class template. Signup and view all the answers

What is the difference between the CamelCase and snake_case styles of naming?

CamelCase is for classes and modules, snake_case is for symbols, methods, and variables. Signup and view all the answers

How do you instantiate a class?

By setting a variable equal to ClassName.new() and passing in any necessary parameters. Signup and view all the answers

How do you set the state of your new instance?

When you pass in the variables required to instantiate it. Signup and view all the answers

What should be done in the #initialize method?

It should set the state of the object and make it usable. Signup and view all the answers

What is a class method?

Class methods are called on a class. Signup and view all the answers

How is a class method different from an instance method?

Class methods are defined on the class itself, while instance methods are defined on objects created from the class. Signup and view all the answers

What is an instance variable?

An instance variable is a variable that belongs to a specific instance of a class. Signup and view all the answers

What's the difference between an instance variable and a 'regular' variable?

Instance variables are associated with an object, whereas regular variables are typically scoped to a method. Signup and view all the answers

What are 'getter' and 'setter' methods used for?

They are used to read from and write to instance variables, respectively. Signup and view all the answers

What is the difference between a 'getter' and a 'setter' method?

'Getter' methods retrieve values from instance variables, while 'setter' methods assign values. Signup and view all the answers

Can a class call its own class methods?

Yes, a class can call its own class methods. Signup and view all the answers

What is scope?

Scope defines the accessibility of variables and methods in different parts of a program. Signup and view all the answers

Study Notes

Classes and Objects

A class is a template from which object instances are created, consisting of variables representing internal state and methods providing behaviors that operate on that state.
Classes are used to group methods that do the smallest possible thing or to construct similar objects.
To create a class, start with the keyword "Class", give the class a name (capitalized and in CamelCase if multiple words), and close with the keyword "end".

Instantiation and State

An instance of a class is an object created from the class template, carrying its own state and having the same behavior as the class.
To instantiate a class, set a variable equal to ClassName.new() and pass in any necessary parameters.
The state of an instance is set by passing in variables required to instantiate it.

Methods

Instance methods are called on an instance of a class, whereas class methods are called on the class itself.
Class methods are declared using the "self" keyword, whereas instance methods are declared without it.
Instance methods are used to perform actions on an instance, while class methods are used to perform actions on the class as a whole.

Variables

Instance variables are variables that are part of an instance, whereas regular variables are local to a method or block.
Instance variables are denoted by the "@" symbol, whereas regular variables are not.
Getter and setter methods are used to access and modify instance variables, respectively.

Inheritance and Scope

Inheritance allows a class to inherit behavior from another class, promoting code reuse.
A subclass can extend a superclass using the "<" symbol, inheriting all its methods and variables.
The "#super" method is used to call a method from a superclass.
Scope refers to the region of the code where a variable or method is accessible.
A new scope is defined when a class, module, or method is defined.

Access Control

Private methods can only be accessed within the class itself, whereas protected methods can be accessed within the class and its subclasses.
Encapsulation refers to the concept of hiding internal implementation details of an object from the outside world.

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Description

Test your knowledge about classes and methods in Ruby programming. This quiz covers key concepts such as implicit returns and how they function within the language. Enhance your understanding of Ruby's quirks and best practices.