General Object-Oriented Programming

Question 1

What is a class?

Answer 1

grouping of variables and methods in a source code file, from which objects can be created. Class is a grouping of variables and methods in a source code file that acts as a template/ blueprint for creating objects

Question 2

What is an interface?

Answer 2

defines methods and holds a group of abstract methods and properties, is used to specify a behavior that classes must implement. ex appliances can all plug into a power outlet

Question 3

What is encapsulation?

Answer 3

binds data and it’s related methods together within a class. It also protects the data by making fields private and giving access to them only through their related methods ex) bank account

Question 4

What is inheritance?

Answer 4

when one class adopt the properties and methods of another class ex) dog and duck are both animals, both make sound and movement but differently

Question 5

What is polymorphism?

Answer 5

the ability of an object to take on many forms ex) woman is a sister, friend, employee

Question 6

***Why would you use an interface instead of inheritance?

Answer 6

you can inherit many interfaces, but only one base class ex) base discount, birthday discount, military discount)

Question 7

What’s the difference between a class and an interface?

Answer 7

A class describes the attributes and behaviors of an object. An interface contains behaviors that a class implements. A class may contain abstract methods, concrete methods. An interface contains only abstract methods.

Question 8

What’s the difference between a class and an object?

Answer 8

Class is a template or blueprint to a house, object is an instance of a class, has their own data, the object is the house

Question 9

Give me an example of where you might want to apply inheritance

Answer 9

Horse, Dog, Elephant inherits from animal

Question 10

Give me an example of where you might want to apply interfaces

Answer 10

two classes for an alarm, one is a phone and one is an alarm clock but they can both be used for alarms or applicances can do different things but all are able to plug into a wall outlet

Question 11

What is an abstract class?

Answer 11

a restricted class that “shows” only essential attributes and “hides” unnecessary information, cannot be used to create objects ex) travel abstract class is country and can use an interface to say iFlyable or iTrainable

Question 12

What is a static method?

Answer 12

a method that only belongs that one class which prevents inheritance, is not stored

Question 13

What is an Array?

Answer 13

collection of elements of the same type, can be individually referenced by using an index to a unique identifier, length cannot be changed

Question 14

What is a static class?

Answer 14

a class that cannot be instantiated

Question 15

define refactoring

Answer 15

allows you to change the code structure without changing or affecting what the code itself actually does// making changes to the code without changing its function, like changing parameter or variable names ex change var name from name to firstName to be more descriptive and differentiate between first, middle and last name

Question 16

What is Functional Programming? How is it different from object-oriented programming?

Answer 16

In functional programming, data cannot be stored in objects, and it can only be transformed by creating functions. In object-oriented programming, data is stored in objects.