Unit 1: Primitive Types

Question 1

What are primitives?

Answer 1

Primitives are the simplest elements available in a programming language. Ex. int, double, char, boolean

Question 2

What is the correct way to initialize a primitive?

a) (Type) (Name) = new (Type)();
b) (Name (Type) = (Value);
c) (Type) (Name) = (Value);
d) (Type) (Name) == (Value);

Answer 2

c) (Type) (Name) = (Value);

ex: int num = 10;

Question 3

What values can int hold?

Answer 3

The int data type stores whole numbers from -2,147,483,648 to 2,147,483,647.

Question 4

What values does double hold?

Answer 4

The double data type stores decimal numbers up to 15 decimal digits

Question 5

What values does char hold?

Answer 5

The char data type stores a single character/letter or ASCII values.

Question 6

What is casting?

Answer 6

Type casting is when you assign a value of one primitive data type to another type.
Ex.

int total = 100;
int numPeople = 40;  
double average = total / (double) numPeople;
//Average will equal 2.5 as a double

Question 7

What is a compound assignment operator?

Answer 7

A simpler way to assign an arithmetic value to a pre-existing value. (+= , /=, *=, -=)

Ex:

int num = 8;
num += 7;
//Now num will equal 15

Question 8

What is the correct way to create a Scanner object?

a) Scanner = new Scanner(System.in);
b) Scanner name = new scanner;
c) Scanner name = new Scanner(System.in);
d) Scanner name = System.in;

Answer 8

c) Scanner objectName = new Scanner(System.in);

Question 9

What does “final” do when used while initializing a primitive?

Answer 9

The word "final" makes it such that you cannot modify the variable after its initialization. 
Ex. final String name = "Chad";
//This String will always be Chad.

Question 10

How do you swap the data stored in two variables of the same type?

Answer 10

Through the use of a temp variable that stores the data of one of the variables so that it is not lost.

For example, if you have variables a and b, and you want to switch their values:

int temp c;
c = a;
a = b;
b = c;

Question 11

What does modulus (%) do?

Answer 11

It returns the remainder of a division operation.

Ex. 25%7 = 4
Ex. 25%5 =0

Question 12

What is a reference type?

Answer 12

An example of a reference value would be a string.

Reference variables store the address of the value.

Question 13

What is the correct way to name a variable?

Answer 13

Variables names must start with a letter, $, or _ and be lowerCamelCase
examples include:
- numApples
- $numApples
- _numApples

Question 14

What does a String hold?

Answer 14

A String holds a list of ASCII characters or numbers. For example any word in the English language.

Ex. String numbers = “123456789101123456789011223344556677”;
String words = “Cat dog mice cows horses !@#$%^&&* more things”;

Question 15

Is a string a Primitive

Answer 15

It is not because it has chars in it

Question 16

int thing = 2*2.2;

Answer 16

4

Question 17

double thing = 2.2 *2;

Answer 17

4.4

Question 18

How do you print things out

Answer 18

System.out.print(“THing”); or

System.out.println(“THings”);

Question 19

What is the Answer of this expression?
4 + 8 * 3 / 4 + 5 % 2 = ?
A.) 5 
B.) 6
C.) 12
D.) 11

Answer 19

D.) 11
PEMDAS don’t forget that modulus is treated as multiplication or division so don’t forget to follow the order of operations.

Question 20

What is the result of the following expression when x is 125?
x % 6

Answer 20

5

Don’t forget that modulus returns the remainder.

Question 21

Which of the following values can correctly be saved in a boolean?
A.)False
B.)Yes
C.)no
D.)true

Answer 21

D.) true

Boolean values in java save true/false values without a capitalized letter