JavaBasics.md

JAVA

DATA TYPES

PRIMITIVE

• byte
• short
• int
• long
  • %d
• float
• double
  • %f
• char
  • %c
• boolean
  • %b

%s is used for String, but its not a primitive datatype.

System.out.printf() can be used or store in a string directly using String.format(<string>, <variables>).

REFERENCED (shallow copy)

• Eg. Date, Point

TYPE CONVERSION

• long 123L
• float 1.3F
• (double)10 is explicit casting

ARRAYS

SINGLE-DIMENSIONAL

• int[] arr = new int[5]

MULTI-DIMENSIONAL

• int[][] arr = new int[2][3]

CONSTANTS

• use final keyword
• uppercase convention

ORDER OF OPERATIONS

1. ()
2. /, *
3. +, -

STRING TO NUMBER

• Integer.parseInt()
• Float.parseFloat()
• etc.

INPUT (SCANNER)

Scanner scanner = new Scanner(System.in);
// now you can use scanner.next<datatype>
byte age = scanner.nextByte();
// single token
String firstName = scanner.next();
// with whitespaces
String fullName = scanner.nextLine();
// ...
scanner.close();

LOOPS

• for
• while
• do-while
• for-each