Chp 2: Using Data

Question 1

declaring/using variables

Answer 1

format:
[datatype] [name/identifier] = [initial value]

ex:
String name = “”;

Question 2

using the boolean Data Type

Answer 2

a logical data type

it’s either true or false

ex:
if ( boolean condition )

Question 3

floating-point data types

float
double

Answer 3

data types that have decimals

double takes up more memory/space than float, so it stores greater values

Question 4

char data types

Answer 4

stores one character

single quotation

Question 5

declaring a constant

Answer 5

makes it possible for the variable to not be changed
changes the variable into a mathematical constant
becomes read only

you use “final”

ex:
final double pi = 3.14159;

Question 6

performing arithmetic using variables and constants

Answer 6

\+
-
/
*
%

Question 7

type conversion

Answer 7

you can use either parse or cast

Question 8

primitive type: the most basic data types available for Java

Answer 8

int
byte, short, int, long

float

double

char

boolean

String

Question 9

strongly typed language

Answer 9

one of the characteristics of Java

you need to tell the variables in advance for Java to understand
variables/datas in Java have several types
Java has many rules

Question 10

assignment operator

Answer 10

=
used to assign a (new) value to a variable

ex:
age = 18;

Question 11

cast operator

Answer 11

to convert a variable into another variable on the fly

( )

ex:
if age is an int,
(double) age

Question 12

uninitialized variable

Answer 12

something that Java does not have this: a variable with no initial value
All variables must be declared and initialized

ex: the initial value of a String variable cannot be null

Question 13

garbage value

Answer 13

random data that will not be used in the program, so it takes up memory for no reason

ex: the value we use to initialize variables

Question 14

block of code

Answer 14

a section of code that’s together

sometimes put within braces { }