Introduction to Variables

Question 1

What are the 8 Primitive data types?

Answer 1

byte, short, integer, long, float, char, double, boolean.

Question 2

what data type has values of true or false?

Answer 2

boolean

Question 3

what data type has values of -128 to 127

Answer 3

byte

Question 4

what data type has values of -32,768 to 32,767

Answer 4

short

Question 5

what data type has values of -2 million to 2 million

Answer 5

integer

Question 6

what data type has values of -9,223,372,036,854,775,808 to 9,223,372,036,854,775,808

Answer 6

long

Question 7

what data type has values of a max of 6 to 7 decimal digits

Answer 7

float

Question 8

what data type has values of @, *, +, a, 1, c

Answer 8

char

Question 9

what data type has values of a max of 15 decimal digits

Answer 9

double

Question 10

What is the difference between a primitive data type vs. reference storage?

Answer 10

primitive variables store the actual values.
reference variables stores the addresses of the objects they refer to.

Question 11

what is the 1 reference data type?

Answer 11

String.

Question 12

what is the syntax to declare a variable and not assign a value?

Answer 12

dataType variableName;

Question 13

when you want to set a variable after its been declared, what do you do?

Answer 13

variable name = value;

Question 14

In variable naming the name cannot include white space, cannot start with a number, cannot be a java reserved word, needs to be unique, and is case sensitive. What should variable naming also do?

Answer 14

variable naming should describe the data it holds.

Question 15

how do you declare multiple variables in one statement? (asking for the syntax you would use)

Answer 15

dataType variableName1, variableame2
ex. String firstName, lastName

Question 16

what is an instance variable?

Answer 16

a instance variable is a variable declared within a class, but outside any methods, constructors, or code blocks.

Question 17

What is this line of code String Title = “Beautiful Day” an example of in this code block?

public class Song {
String Title = “Beautiful Day”;
String Artist;
public void SetArtist (String Singer) {
Artist = Singer;
}
}

Answer 17

an instance variable

Question 18

How would you print data in java?

Answer 18

System.out.println();

Question 19

what is the syntax to declare an array?

Answer 19

dataType[] variableName = {“thing1”, “thing2”, “thing3”};