Constants

Integer Constants

• An integer constant can be of decimal, octal or hexadecimal type.
  • Decimal constants begin with a non-zero digit
  • Octal constants begin with a zero
  • Hexadecimal constants begin with "0x" or "0X"
• As a language extension, QA C also supports binary constants which are prefaced with the digits "0b" or "0B".
• An integer constant may also be appended with a suffix. The letters "u" or "U" indicating unsigned and "l" or "L" indicating type long can be applied in any order..
• Integer constants are always of type int, unsigned int, long or unsigned long. Constants of type char or short can only be constructed using a cast, e.g. "(unsigned char)0x1F"

Character Constants

• Are represented by one (or more) characters enclosed in single quote marks e.g. 'a'.
• Are implemented in type int - not type char.
• Escape sequences are of three types:
  • Simple escape sequences are used to represent common control characters.
    • \a      alert
    • \b      backspace
    • \f      form feed
    • \n      new line
    • \r      carriage return
    • \t      horizontal tab
    • \v      vertical tab
  • Hexadecimal escape sequences take the form: '\xFE8A'.
  • Octal escape sequences take the form: '\015'.

Character Strings

• Are represented by a sequence of characters enclosed in double quote marks e.g. "static analysis".
• May include any member of the source character set except the double-quote ", backslash \ or new-line character.
• May include escape sequences as allowed in character constants.

Floating Constants

• Take the form of a signed non-integer number e.g. 12.74
• May also include a signed exponent e.g. 12.74E3 or 41.98E-5
• By default, floating constants are of type double.
• A constant of type float  must have a suffix F or f.
• A constant of type long double must have a suffix L or l.

Index