Objects - Inheritance

Question 1

What are the four core principles of OOP?

Answer 1

Encapsulation, inheritance, polymorphism and abstraction.

Question 2

Subclasses

Answer 2

Subclasses inherit the attributes and behaviors of the more general classes.

When you write a class, you usually want to try and make it as general and open ended as possible so that you can reuse it in other programs that you write.

A subclass is taking a more general class and then adding the needed functionality to it that is specific to the current program that you are working on.

Question 3

How do you spewcify a class as a subclass?

Answer 3

You add a colon after the name of the SUBclass that you are making, followed by the name of the CLASS that you are extending.

class NewSubClass : OriginalClass
{

}

Question 4

When creating a subclass, what do you need to make sure and do when adding it’s parameters?

Answer 4

You need to include the base class’s parameter’s as well so that they can be satisfied.

You do this by adding a colon after the SUBCLASS’s parameters have been laid out, then adding the keyword “base” followed by the parameters that the base class takes.

public NewSubClass (int x, int y) : base(x, y)
{

}

Question 5

What are other terms for base class?

Answer 5

Parent Class or Super Class

Question 6

What are other names for Sub Class?

Answer 6

Child Class or Derived Class

Question 7

What does the “is” operator do?

Answer 7

It will return true if a variable is of a given type.
You use this to preform a type check.

Console.WriteLine(x is MapLocation);

will tell you T or F as to weather or not x is of the type MapLocation.

Question 8

What are exceptions used for?

Answer 8

They are used to communicate that an error has happened.

Question 9

How do you create an object of an exception that you’ve made?

Answer 9

In the catch declairation, you add a variable name in the parameters next to the exception’s name.

catch(Exception ex)
{
Console.WriteLine(ex.Message);
}