Ch 2: Language Fundamentals

Ch 2: Language Fundamentals

1. ENCODING SETS

   • ASCII
     • American Standard Code for Information Interchange
       • Used in Java for input elements, except comments, identifiers, and the contents of characters and strings
   • Unicode
     • Attempts to include all characters in all languages in the world into a single character set
       • Java supports Unicode characters for comments, identifiers, characters and strings
       • Character Encoding makes it easier and more efficient to store and transmit Unicode

2. SEPARATORS

   • Help define the structure of the program
   • Parentheses ( )
     • Method signatures, narrowing conversions, loops to contain expressions to be evaluated
   • Braces { }
     • Declaration of types, blocks of statements, array initialization
   • Brackets [ ]
     • Array declaration, array value dereferencing
   • Angle Brackets < >
     • Pass parameter to parametrized types
   • Semicolon ;
     • Terminate statements, in the 'for' statement to separate initialization code, expression, & the update code
   • Colon :
     • 'For' statement that iterates over an array or collection
   • Period .
     • Separate package names from subpackages & type names, separate field or method from reference variable

3. PRIMITIVES

   • Simple non-object programming elements that represent numbers and simple values
   • byte
     • Byte-length integer (8 bits)
   • short
     • Short integer (16 bits)
   • int
     • Integer (32 bits)
   • long
     • Long integer (64 bits)
   • float
     • Single-precision floating point (32-bit IEEE 754)
   • double
     • Double-precision floating point (64-bit IEEE 754)
   • char
     • A unicode character
   • boolean
     • boolean value (T/F)

4. VARIABLES

   • Data placeholders whose contents can change, must have:
     • Declared data type
       • Reference Types
         • Provides reference to an object
       • Primitive Types
         • Holds a primitive
     • Name or Identifier
       • Must begin with a Java letter
       • Must not be a Java keyword, boolean literal or null literal
       • Must be unique within its scope

5. CONSTANTS

   • Variables whose values, once assigned, cannot be changed
   • Declared by using keyword 'final'
   • Constant names are all in upper case with words separated by underscores

6. LITERALS

   • Need to assign values to variables in a format that the Java compiler understands
   • Literals of Primitive Types
     • Integer Literals
       • May be written in decimal, hexadecimal, or octal
       • Used to assign values to variables of types byte, short, int, and long
     • Floating-Point Literals
       • Whole number part, decimal point, fractional part, optional exponent
       • Used to assign values to variables of types float and double
     • Character Literals
       • Unicode character or an escape sequence enclosed in single quotes
         • An escape sequence is a representation of a unicode character that cannot be entered using the keyboard or that has a special function in JAva
     • Boolean Literals
       • Has 2 values; True or False
   • String Literals
   • Boolean Literals