Variables

Declarations

Assignments

Variable Naming

Begin with a letter (a-z/A-Z)
After the initial letter, may also contain letters, digits (0-9), underscore (_), or dollar sign ($)
Not a keyword or reserved word http://docs.oracle.com/javase/tutorial/java/nutsandbolts/_keywords.html
Case sensitive
Disarankan:
- Tidak dimulai dengan huruf kapital
- camelCase
- Meaningful
  sum address2
  first name phone
  first_name phone number
  firstName double
  FirstName static
  FIRSTNAME e-mail
  1stName GradeTest#1
  Address homepageURL
  address homepageUrl
  address1 …


sum	address2
first name	phone
first_name	phone number
firstName	double
FirstName	static
FIRSTNAME	e-mail
1stName	GradeTest#1
Address	homepageURL
address	homepageUrl
address1	…

Declaring Variables

Data Types

Type	Explanation	Min	Max
int	32-bit (4-byte) integers	-2,147,483,648	2,147,483,647
short	16-bit (2-byte) integers	-32,768	32,767
long	64-bit (8-byte) integers	-9,223,372,036,854,775,808	9,223,372,036,854,775,807
byte	8-bit (1-byte) integers	-128	127
float	32-bit (4-byte) floating point numbers	$\pm$ 1.40129846432481707e-45	$\pm$ 3.40282346638528860e+38
double	64-bit (8-byte) floating point numbers	$\pm$ 4.94065645841246544e-324d	$\pm$ 1.79769313486231570e+308d
char	Unicode characters	0	65,535
boolean	true or false	-	-
String	Text	-	-

Printing Variables

System.out.println(variable);
System.out.print(variable);

Operators

System.out.println(quantity * price);
sum = sum + 1;
System.out.println(10 - 2);
System.out.println(sum / 5);
System.out.println(-total);

Arithmetic Operators

int a = 10, b = 5;

+ (Addition), e.g.: a + b equals 15

- (Subtraction), e.g.: a - b equals 5

* (Multiplication), e.g.: a * b equals 50

/ (Division), e.g.: a / b equals 2

% (Modulus), e.g.: a % b equals 0

++ (Increment), e.g.: a++ equals 11

-- (Decrement), e.g.: a-- equals 9

int a = 10; // variable declaration
// addition (+)
System.out.println(a + 1);
System.out.println(a);
// increment
System.out.println(a++);
System.out.println(a);
// another increment
a++;
System.out.println(a);

Operators for Strings

String message = "Welcome";
System.out.println(message);

String message = "Welcome ";
String name = "Arif";
System.out.println(message + name);

String message = "Welcome ";
String name = "Arif";
message = message + name;
System.out.println(message);

String message = "Welcome ";
String name = "Arif";
message = message + name + "!";
System.out.println(message);

String message = "Welcome ";
String name = "Arif";
message = message + name + "!";
System.out.println(message);
int date = 15;
int month = 9;
int year = 2016;
String message2 = "Today's date is " + date;
System.out.println(message2);

Persiapan Belajar

Materi

Task

Programming by Doing

Compiler

Variables and Operators

Variables

Variables

Declarations

Assignments

Variable Naming

Declaring Variables

Data Types

Printing Variables

Operators

Arithmetic Operators

Operators for Strings

​Variables

​Variables

​Declarations

​Assignments

​Variable Naming

​Declaring Variables

​Data Types

​Printing Variables

​Operators

​Arithmetic Operators

​Operators for Strings

Variables

Variables

Declarations

Assignments

Variable Naming

Declaring Variables

Data Types

Printing Variables

Operators

Arithmetic Operators

Operators for Strings