CSE 1321 Exam 3

Question 1

*Represent the concept of things in the real world (example: Dogs)

Follow the template:
- name
- variables (aka attributes)
- functions (aka methods, behaviors, method functions)

Answer 1

Classes

Question 2

These are what the object IS made up of

Answer 2

Variables relation to objects

Question 3

These are what the object CAN DO

Answer 3

Functions relation to objects

Question 4

What would the smallest class look like?

Answer 4

class ClassName{
}

Notice that there is no MAIN here

Question 5

*Has attributes
*Has a constructor whish is used to intialize attributes
*Has other methods
*Template for creating objects
*Creates a new complex data type
EXAMPLE: blueprints for a house

Answer 5

Class
*A class is basically just you creating a data type and it doesn’t need to run any code unless you tell it to.

Question 6

*Is an instance of a class
*has a state(variables) that is independent from others
EXAMPLE: your specific house with specific colors and finishes

Answer 6

Object

Question 7

What is the purpose of a constructor

Answer 7

to initialize objects

Question 8

Can you have multiple constructors?

Answer 8

Yes; this is known as constructor overloading

Question 9

What happens if you don’t create a constructor

Answer 9

an “invisible” default constructor is made automatically. Otherwise you wouldn’t be able to create objects.

Question 10

When creating a constructor, the parameters should be only what we know (true/false)

Answer 10

true

Question 11

If an object’s state is constant, we should set it as a parameter of the constructor (true/false)

Answer 11

false

Question 12

(Java) What is the purpose of using “this. “?

Answer 12

“this. “ tells the program that the variable after the dot operator is a variable inside that class. It is used commonly with constructors and methods.

Question 13

Constructor names must match the name of the class they are in. (true/false)

Answer 13

True

Question 14

What is another word for SETTER?

Answer 14

Modifier or Mutator
(Note that the public and private keywords are known as ACCESS modifiers)

Question 15

What is another word for GETTER?

Answer 15

Accessor

Question 16

What is the purpose of GETTERS and SETTERS?

Answer 16

They help with encapsulation which increases protection. By making variables private and creating GETTERS and SETTERS, you limit the ways in which someone can alter the private data.

Question 17

Is there a way to access private variables from outside a class?

Answer 17

Yes, if the private variables are in a class that also has non-private GETTER and SETTER methods for the private variables, you can access the variables from anywhere.

Question 18

When variables are private, where can you directly access them from?

Answer 18

Only the class they are inside will have access to the variable. Same goes for methods.

Question 19

When variables are public, where can you access them from?

Answer 19

Any class can refer to the variable. Same goes for methods.

Question 20

You can create multiple classes in one file. How many of these classes can be listed as PUBLIC?

Answer 20

Only one can be listed as public, and it has to match the file name.
All other classes will just be instantiated as class.

Question 21

can a SETTER method return more than one value?

Answer 21

SETTER methods don’t return value, they only set them, so the return type is VOID

Question 22

do SETTER methods need parameters?

Answer 22

Yes. The parameters will be whatever value you are setting. If you are setting the name of a dog to Sparky, your SETTER parameter will be a string.

Question 23

in the context of this class, do GETTER methods typically have parameters?

Answer 23

no. the purpose of the GETTER method is only to access a private value and return that value.

Question 24

An object’s method is called by

Answer 24

writing the objects name followed by the dot operator and the method name

Question 25

Object Oriented Programming is categorized by use of

Answer 25

classes and objects

Question 26

which keyword is reserved for creating objects?

Answer 26

new

Question 27

Strings are primitive data type that can use the + operation

Answer 27

false. strings are non-primative