Intro to programming UNIT 2

Question 1

How many characters does ASCII and UNICODE share?

Answer 1

The first 256 Characters

Question 2

Why do you specify datatypes

Answer 2

It tell the compiler how much memory to set aside for the variable and how to interpret the data in memory

Question 3

What naming convention do you use for a class

Answer 3

TitleCase. Every word is capitalized and has no spaces

Question 4

What are the datatypes for whole numbers and how many bits does each use

Answer 4

byte (8 bits)
short (16 bits)
int (32 bits)
long (64 bits)

Question 5

What is the naming convention for variable names

Answer 5

camelCase. The first word is not capitalized and every word after is capitalized

Question 6

What makes a valid variable name

Answer 6

Must start with a letter, underscore or a dollar sign
Cannot start with a digit
Not a java reserved keyword

Question 7

What is the naming convention for constants

Answer 7

Every Letter is capitalized and spaces are underscores

TAX_RATE

Question 8

How do you declare a constant?

Answer 8

Using the final keyword

Question 9

What are variable names also known as

Answer 9

Identifier
Reference
Handle

Question 10

What is the only thing in java that is not an object?

Answer 10

Primitive data types

Question 11

How many primitive datatypes are there in java

Answer 11

Eight

Question 12

What are the two non numeric data types? And what are their sizes?

Answer 12

char (16 bits) - will hold a single unicode value
boolean (8 bits) - will hold a true false value

Question 13

What are the signed floating point data primitives and their sizes

Answer 13

float (32 bits)
double (64 bits)

Question 14

What is the var datatype?

Answer 14

It’s an inferred datatype. The compiler looks at the data going into the variable and chooses the correct data type for it

Question 15

When can you use the var datatype?

Answer 15

It can only be used when creating local variables within a method

Question 16

What is a data literal?

Answer 16

A data literal is data stored within a program

i.e: int ryanAge = 22;

22 would be the data literal

Question 17

How do you indicate that a data literal is a certain type?

Answer 17

When the var is a long add L to the suffix

i.e: long ryanAge = 10000000000000L;

Suffix a long by an L for it to be considered a long instead of an int

Question 18

What happens when you divide two integers?

Answer 18

Java will truncate the result.

ie: 5 / 2 = 2.

it will simply remove the decimal point. IT WILL NOT ROUND OFF NUMBERS

Question 19

What do you call a variable?

Answer 19

An identifier

Question 20

What does ‘m’ represent

Answer 20

It represents a char literal

Question 21

How do you get 1 char from the Scanner?

Answer 21

input.next().charAt(0);

Question 22

When the compiler assumes the conversion what is this called

Answer 22

An implicit conversion

Question 23

What is an operator

Answer 23

An operator is a symbol that performs built-in calculations

Question 24

How do you import the random function

Answer 24

import java.util.Random;

Question 25

How do you create a Random object (java.util.Random) named randGen

Answer 25

Random randGen = new Random();

Question 26

How do you get a random integer from a Random object named randGen

Answer 26

randGen.nextInt();