Chapter 4 - Methods use instance variables

Question 1

Point of an object

Answer 1

Has behavior that acts on it’s state

Question 2

Methods use

Answer 2

Instance variable values

Question 3

A method uses

Answer 3

Parameters

Question 4

A caller passes

Answer 4

Arguments

Question 5

What do you have to do if a method takes a parameter

Answer 5

You must pass it a value of the appropriate type

Question 6

Arguments are

Answer 6

The things you pass into methods

Question 7

A parameter is nothing more than

Answer 7

A local variable with a type and a name that can be used inside the body of the method

Question 8

An example of an argument

Answer 8

d.bark(3); <— 3

Question 9

An example of a parameter

Answer 9

void bark (int numOfBarks) <—numOfBarks

Question 10

What does void mean?

Answer 10

Methods do not return anything back

Question 11

Can methods have multiple parameters?

Answer 11

Yes. t.takeTwo(12, 34);

Question 12

Java is?

Answer 12

Pass-by-value

Question 13

What does pass-by-value mean

Answer 13

Pass-by-copy

Question 14

Call the go()method, passing the variable x as the argument

Answer 14

foo.go(x);

Question 15

Value means?

Answer 15

bits inside the variable. A variable is a reference to an object.

Question 16

A method must

Answer 16

Declare a return type

Question 17

What is the purpose of a getter

Answer 17

To send back, as a return value, the value of whatever it is that particular Getter is supposed to be Getting

Question 18

What is the purpose of a setter

Answer 18

To take an argument value and use it to SET the value of an instance variable

Question 19

How do you hide data

Answer 19

With the public and private access modifiers

Question 20

An encapsulation starter rule of thumb

Answer 20

Mark your instance variables PRIVATE

Provide PUBLIC getters and setters for access control

Question 21

Declare and create a Dog array to hold 7 Dog references

Answer 21

Dog [] pets;

pets = new Dog [7];

Question 22

Instance variables always get a

Answer 22

Default value.  
Booleans -- Flase
References -- Null
Ints -- 0
Floats -- 0.0

Question 23

Why don’t you have to initialize instance variables

Answer 23

Because they always have a default value

Question 24

What is the default value for a reference variable

Answer 24

null

Question 25

The difference between instance and local vairables

Answer 25

1. Instance variables are declared inside a class but not within a method
2. Local variables are declared within a method
3. Local variables MUST be initialized before use

Question 26

Do local variables get a default value

Answer 26

No.

Question 27

What do you need to determine if two objects are equal

Answer 27

The .equals()method

Question 28

The == is used only to compare?

Answer 28

The Bits in two variables

Question 29

When do you use ==

Answer 29

To compare two primitives, or to see if two references refer to the same object

Question 30

When do you use the equals method

Answer 30

To see if two different objects are equal

Question 31

A method uses …..

Answer 31

Parameters

Question 32

A caller passes

Answer 32

Arguments