lecture 3

• Variable


  A named quantity that is stored in the computer memory (RAM)

  
• Variable


  • Different types such as double, integer, character, etc.
  • Computers store them differently based on their memory requirements

  
• In Java, the compiler needs to know the type of variable being used first

  
• Variable types

  • Integer
  • Double
  • Character
  • String
• Primitive data types in Java

  • Byte
  • Short
  • Int
  • Long
  • Float
  • Double
  • Char
  • Boolean

  
• Primitive data types


  The basic data types in Java

  
• Choosing a suitable variable name

  1. Start with a letter, underscore or dollar sign

  2. Can contain letters and digits 0-9 after first character

  3. No spaces or special characters

  4. Case sensitive

  5. Avoid using Java keywords
• Variable names that describe the data stored are called mnemonic variables
• Assignment operator (=)


  Used to initialize a variable with a value
• Unary operators


  • Increment (++)
  • Decrement (--)
  • Negation (-)
  • Logical complement (!)