​

Variables

​

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	…

​

Declaring Variables

​

Data Types

​

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

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);