Classes, Methods And Attributes

Question 1

What is a “Class”?

Answer 1

It is the thing you make in a program that represents a physical thing in the world. Or rather, a category of digitalised versions of specific things in the world.

For example, “Animal” can be a class containing specific reptiles, amphibians, fishes and land mammals in a program.

It’s important to remember that these are digitised versions of our concepts of the world.

Question 2

What is a method?

Answer 2

It’s what describes what actions a class or object can do. In computer science, this is a piece of code that does something specific, and usually leads to changing the value of an attribute.

Question 3

What is an attribute?

Answer 3

An attribute describes the properties of an object or class. As a rule of thumb, try to make a method for every attribute. The values an attribute has better be changed by methods.

Question 4

What are some elements of an attribute?

Answer 4

Visibility modifier, data type, attribute name, default value, semicolon.

Question 5

What are the elements of a method?

Answer 5

Visibility modifier, return type, method name, parameter list, method body.

Question 6

What does the visibility modifier private mean for an attribute?

Answer 6

For a class Customer with attributes lastName, firstName, sex and birthDate with private as a visibility modifier, this means that the attributes are “visible” or “accessibile” only inside the class.