This document discusses basic data storage in programming, including constants, variables, primitive data types, default values, possible values, variable names, and samples. It defines constants as data that never changes, variables as storage places for potentially changeable data, and primitive data types like boolean, byte, char, String, short, int, long, float, and double. It also covers initializing variables, default values for each data type, possible value ranges, naming conventions for variables, and examples of declaring different variable types.

1. Basic Data Storage

2. Constants
Data that never changes

3. Constants
true
89
4.6
'k'
"Sunnyvale"

4. Variables
A storage place for data that you can refer to by
name and may be changeable

5. Initializing Variables
Specify what
kind of data
to store
type name = value;
Set it to an initial
Give it an identifier
value

6. Primitive Data Types
boolean short
byte int
char long
String float
double

7. Default Values
boolean false
byte 0
char 'u0000'
String null
short 0
int 0
long 0L
float 0.0f
double 0.0d

8. Possible Values
boolean false, true
byte -128 to 127
char 'u0000' to 'uffff'
String ""
short -32,768 to 32,767
int -2,147,483,648 to 2,147,483,647
long -9,223,372,036,854,775,808 to
9,223,372,036,854,775,807
float 32-bit floating point
double 64-bit floating point

9. Variable Names
a-z, A-Z, 0-9, _, $
begin with a-z, A-Z, _, $
usually begin with a-z
$ rarely used
case sensitive: a ≠ A
camel case

10. Variable Names
valid preferred
$firstName firstName
_lastName lastName
Age age
zip_code zipCode
CITY city
rel2Per relationshipToPerson
addressline2 addressLine2
c count

11. Samples
boolean flag = true;
byte b = 0;
char character = 'a';
String firstName = "Marisa";
short age = 13;
int revolutionsPerHour = 65000;
long grainsOfSand = 14789409243948903;
float length = 21.5;
double pi = 3.1415926535897;