Module 2: Representing Infomation

Question 1

What are the two types of variables?

Answer 1

Reference and Primitives’

Question 2

What is a print statement?

Answer 2

A print statement is how we get a command to print to our console.

Question 3

What is a variable

Answer 3

Something that represents a piece of data. The value may or may not be known at the time of declaration (creation) and can be changed.

Question 4

What is a Primitive?

Answer 4

A primitive is for storing simple values… int, float, double, long, boolean, char, byte, and short.

Question 5

What is a reference variable?

Answer 5

A reference variable stars, a memory address of an object. We say that the variable “refers” to the object.

Question 6

System.out.println();

Answer 6

Java method that lets us print out a line of output, followed by a newline to the user.

Question 7

System.out.print();

Answer 7

Prints output without a newline

Question 8

What is a data type?

Answer 8

Indicates the type of data, a memory, location (variable or named constant) can store.

Question 9

What are the different data types in Java?

Answer 9

int, float, double, short, byte, boolean, long, and char…
String in Java is actually a non-primitive data type

Question 10

Boolean

Answer 10

A single value of either TRUE or FALSE

Question 11

char data type

Answer 11

Used to hold any single character

Question 12

int data type

Answer 12

A primitive data type that represents integer values. Ranges from -2147483648 to 2147483648

Question 13

float data type

Answer 13

Holds a floating point value of up to six or seven significant digits ID accuracy

Question 14

double data type

Answer 14

Can hold a floating point value of up to 14 or 15 significant digits of accuracy

Question 15

short data type

Answer 15

holds small integers from -32,768 to 32,767

Question 16

byte data type

Answer 16

holds very small integers from -128 to 127

Question 17

long data type

Answer 17

Holds very large integers from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807

Question 18

What data type uses single quotes?

Answer 18

char

Question 19

Anything with “” is considered?

Answer 19

A String

Question 20

What is a literal?

Answer 20

A literal is the sequence of characters used in a program to represent a constant value. For example, ‘A’ is a literal that represents the value A of type char and 17L is a literal that represents the number 17 as a value of type long. A literal is a way of writing a value and should not be confused with the value itself.

Question 21

What is an instance variable?

Answer 21

Instance variables are variables within a class but outside any method. These variables are instantiated when the class is loaded. i.e. The values are not present until an object is created.

Question 22

What is a local variable?

Answer 22

Variables are defined inside methods, constructors or blocks are called local variables. The variable will be declared and initialized within the method and it will be destroyed when the method has completed.

Question 23

What does it mean to initialize a variable?

Answer 23

Have a value assigned to the variable. In other words to give it the first value the variable will hold as this value can be changed later in the application.

Question 24

What does it mean to declare a variable?

Answer 24

To reserve the space in memory (ex: int x;). In other words to create a variable but do not assign it a value right away. You can initialize the variable later in the code.