Exercises
Explore Ruby metaprogramming with this quiz on the language’s dynamic object model and runtime programming features. Test your understanding of adding methods to classes, using attr_accessor, reopening classes, and working with self and super. Questions also cover inheritance hooks such as inherited, module inclusion callbacks, undefining methods, dynamically defining class methods, and accessing instance variables with instance_variable_get. Ideal for Ruby developers, students, and programmers who want to strengthen their knowledge of dynamic classes, modules, callbacks, and reflective techniques.
Answer the questions below and check the explanation for each answer.
0/10 answered
Auto audio on: the next questions will be read aloud when you click Continue.
The correct answer is Option 3) define_method. This Ruby method allows you to add methods to a class at runtime by defining them within the class, providing flexibility to dynamically create methods as needed.
The attr_accessor :x in Ruby creates both getter and setter methods for the instance variable @x. It allows you to read and modify the variable directly through x and x= methods, respectively. It does not directly create an instance variable or a private method, hence options 1 and 2 are incorrect.
The method class_eval is commonly used in programming languages like Ruby to dynamically open a class for modifications. It allows you to evaluate a block of code in the context of a class, enabling the addition, modification, or removal of methods at runtime.
The self keyword in Python is used within a class to refer to the instance of the class that is currently being used. It allows access to the instance's attributes and methods from within the class.
The super keyword in Ruby is used to call a method with the same name from the parent class of the current class. This allows you to incorporate behavior from the superclass into your subclass, making it possible to extend or override functionality while still utilizing the code of the superclass method.
The hook method called when a subclass is derived from a current class is known as inherited. When a new class is created based on an existing class, this method can be used to perform operations or checks necessary for the inheritance process.
The Module#included hook method in Ruby allows you to Run code after a module is included into another class or module. It is a callback method that is automatically called when the `include` method is used in a class, enabling you to execute additional setup or configuration code.
In Ruby, to undefine a method, you use the remove_method construct. This will remove the method from the class or module, where it was defined and it will be like the method never existed. On the other hand, undef_method is not a valid syntax to remove or undefine a method in Ruby.
To dynamically define a class method in Ruby, you would use the singleton_class.define_method method. This is because class methods are singleton methods on the class object itself, and the singleton_class provides a way to access the object's singleton class where these methods can be defined.
The method instance_variable_get is used to return the value of an instance variable. It allows access to the variable's value outside the usual encapsulation if given the variable's symbol or string reference name.
Free CourseLearn Python
5
(3)
13h00m
17 exercises
Free CourseJava Programming
5
(4)
9h15m
48 exercises
Free CourseCreate Desktop App
5
(4)
5h33m
30 exercises
Free CourseRuby on Rails
5
(7)
9h39m
34 exercises
Free CourseJava
4.8
(56)
22h17m
28 exercises
Free CourseC# Sharp for beginner
4.8
(37)
3h55m
15 exercises
Free CourseC++ as your first Programming Language
4.8
(107)
5h12m
23 exercises
Free CourseJava for beginners
4.8
(183)
26h50m
49 exercises
Thousands of online courses in video, ebooks and audiobooks.
To test your knowledge during online courses
Generated directly from your cell phone's photo gallery and sent to your email
Download our app via QR Code or the links below:.
Carry knowledge in your pocket.
Download the Cursa app.
There are hundreds of free courses available, with a free certificate of completion that is saved in your mobile image gallery.
Download the app to access the Course Completion Certificate for Free.
+ 10 million
students
Free and Valid
Certificate
60 thousand free
exercises
4.8/5 rating in
app stores
Free courses in
video and ebooks