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1.5 Numbers

Numbers are by default denoted in decimal notation. Real (or decimal) numbers are written using engineering or scientic notation (e.g. 0.314E1).

For integer type constants, Free Pascal supports 4 formats:

  1. Normal, decimal format (base 10). This is the standard format.
  2. Hexadecimal format (base 16), in the same way as Turbo Pascal does. To specify a constant value in hexadecimal format, prepend it with a dollar sign ($). Thus, the hexadecimal $FF equals 255 decimal. Note that case is insignicant when using hexadecimal constants.
  3. As of version 1.0.7, Octal format (base 8) is also supported. To specify a constant in octal format, prepend it with a ampersand (&). For instance 15 is specied in octal notation as &17.
  4. Binary notation (base 2). A binary number can be specied by preceding it with a percent sign (%). Thus, 255 can be specied in binary notation as %11111111.

The following diagrams show the syntax for numbers.

_________________________________________________________________________________________________________ Numbers
-- --hex digit sequence|hex digit-------------------------------------- 6---------

-- --octal digit sequence|octal digit------------------------------------ 6----------

-- --bin digit sequence---1 ------------------------------------------- 6-0 -|| ------|

-- -- --- -------------------------------------------- digit sequence 6digit-|

-- -|---- -------------------------------- -- unsigned integer|- - digit sequence --| - |-$ -hex digit sequence| % bin digit sequence

-- --sign|+ -------------------------------------------------------- -----

-- --unsigned real digit sequence -|-----------------|------------------- -.-digit sequence- -scale factor--

-- --scale factor-|E ---|------digit sequence--------------------------- -e -- -sign--

-- --unsigned number---unsigned real---------------------------------- -unsigned integer-|

-- -- --------- ---------------------------- signed number -sign -| unsigned number
___________________________________________________________________

Remark: It is to note that all decimal constants which do no t within the -2147483648..2147483647 range, are silently and automatically parsed as 64-bit integer constants as of version 1.9.0. Earliers versions would convert it to a real-typed constant.

Remark: Note that Octal and Binary notation are not supported in TP or Delphi compatibility mode.

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