Variables and Expressions

Practical C chapter 4, K&R chapter 2.

• Variables

  • names: letters, numbers, and underscores. start with letter. case sensitive, as is everything in C (and UNIX in general).
  • types
    • int (Integers are whole numbers)
    • float (numbers with a decimal point)
      • 3.14
      • 6.4e4
      • 1e-6
    • type conversion
    • char
      • escape sequences: \b \f \n \r \t \' \" \\ \a
  • (arrays)
    • string
      • an array of characters
      • null termination
  • printf:
    • %d (decimal integer)
    • %f (floating point)
    • %c (character)
    • %s (string)

• Operators

  • arithmetic: * / + - % ++ --
  • logical: > >= < <= == != && || !
    • ternary x = e ? a : b is the same as if (e) { x = a } else { x = b }
  • shortcuts: += -= *= /= %=
  • precedence