Language Fundamentals

Language Fundamentals

1. Encoding Sets

   • ASCII
     • Character set representing alphanumeric characters, with each character being represented by 7 bits. This makes 128 characters including lower and upper case Latin letters, number, and punctuation marks
   • Unicode
     • Includes all characters in all languages in the world in one single character set. Initially represeted by 16 bits, but a 32 bit system is more convenient to store as many as a million characters
   • Separators
     • Parentheses, Braces, Brackets, Angle brackets, Semicolons, Colons, Commas, and Periods

2. Primitives

   • byte (Byte-length integer), short (Short integer), int (Integer), long (Long integer), float (Single-precision floating point), double (Double-precision floating point), char (A Unicode character), boolean (a boolean value)

3. Variables

   • Two data types: reference types and primitive types
   • Rules for choosing an identifier: 1) UNlimited-length sequence of Java letters and Java numbers, but must begin with a Java letter, 2) Must not be a Java keyword, a boolean literal, or the null literal, 3) Must be unique within its scope

4. Constants

   • Cannot be changed once assigned, Created using the word final and by convention the names are in all upper case with words separated by underscores

5. Literals (of primitive types)

   • Integer Literals
     • May be written in decimal, hexadecimal, or octal and are used to assign values to variables of types byte, short, int, and long
   • Floating-Point Literals
     • Inludes: a whole number part, a decimal point, a fractional part, and an optional exponent. Additionally, float is 32 bits in size and double is 64 bits in size
   • Character Literals
     • A Unicode character or an escape sequence enclosed in single quotes
   • Boolean Literals
     • Two values: true or false