Language Fundamentals

Language Fundamentals

1. ASCII and Unicode

   • Unicode is used in JAVA and ASCII is included in unicode
   • Unicode represented by 32 bits, (16 bits can represent more than 65,000 characters)
   • Java uses ASCII for almost all input elements, except comments, identifiers, and the contents of characters and strings

2. Separators

   • () Parentheses
     • Method signatures, expressions to raise operator precedence, narrowing conversation, loops to contain expressions to be evaluated
   • {} Braces
     • Declaration of types, blocks of statements, array initialization
   • [] Brackets
     • Array declaration and value dereferencing
   • <> Angle brackets
     • Used to pass parameters to parameterized types
   • ;Semicolon
     • Used to terminate statements and separate codes
   • : Colon
     • Used in a for statements that iterates over an array
   • , Comma
     • Used to separate arguments in method declarations
   • Period
     • Used to separate package names from subpackages and type names; separate a field or method from a reference table

3. Primitives

   • Data type, like objects
   • Represent Numbers
     • Byte, short, int, long, float, double
   • Represent integers or whole numbers
     • Byte, short, int, long
   • A char type can contain a single Unicode character; a boolean contains true or false

4. Variable

   • Data Placeholders
   • Java requires variables with a declared type
     • Ex of a variable: int rowCount;
   • Reference type: provides a reference to an object
   • Primitive types: holds a primitive

5. Constants

   • Variables whose values, once assigned, cannot be changed
   • Created by using keyword final

6. Literals

   • Literals of primitive types, string literals, null literals; only primitive types are discussed
     • Integer Literals
       • Assign values to byte, short, int, long
       • Must not assign a value that exceeds the capacity of a variable
     • Floating-Point Literals
       • A whole number part, a decimal point, a fractional part, an optional exponent
       • double: 64 bits in size
       • float: 32 bits in size
     • Boolean Literals
       • Two values: True and False
     • Character Literals
       • A unicode character, or an escape sequence