Language Fundamentals

Language Fundamentals

1. Encoding Sets

   • Unicode is a character set that represents more than 65,000 characters and used by many programming languages
     • Problem: so much data to transfer --> encoding allows us to use Unicode when writing comments, identifiers, characters, and strings. UTF-8 is the most popular
   • ASCII (American Standard Code for Information Interchange) character set is the standard character set and represents 128 characters

2. Primitives

   • 8 different data types that are used to represent numbers, characters, and specific phrases
     • byte, short, int, long, float, and double all represent integers or decimals
     • char contains a single character like 'd', '&' ,or '4'
     • boolean returns either true or false

3. Variables

   • Variables represent data and must have a declared type
     • Reference types refer to objects and primitive type
   • Variables also have a name (can't be a Java keyword, boolean, or null)
   • Declare a variable by writing the type followed by the name and a semicolon
     • int rowCount; or char c;
     • Can combine variables with the same type by separating with a comma
       • int a, b; = int a; int b;
       • Possible to assign value at the same time as you declare a variable
         • int rowCount = 100;

4. Constants

   • Constants are variables that have values that can't be changed
     • Declare a constant using keyword 'final'
       • Constants are all uppercase with words separated by underscores
         • final int ROW_COUNT = 50;

5. Literals

   • Integer Literals
     • Assign values to primitives: byte, short, int, and long
       • Can't assign value to a literal when it's outside the allowed values
         • byte b = 200; doesn't work because byte can go from -128 to 127
     • Written in decimal(base 10), base 16, or base 8
     • 2 or int x = 2;
       • 1_000_000
   • Floating-point Literals
     • 0.2, .2, 7.33, 0.7 e^12
     • Consists of: whole number part, decimal part, fractional part, optional exponent
     • Two types: Float = 32 bits // Double = 64 bits
       • use f or F to create a float, if not, automatically becomes a double
         • 8.f or 0.5f // 12.53
   • Character Literals
     • A single character enclosed in single quotes
       • 'a' // '%' // 'R'
     • Escape sequenses can't be entered using the keyboard but can be represented with a character literal
       • '\b' = backspace character // '\t' = tab character // '\\' = backslash
   • Boolean Literals
     • Returns two values: true and false