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+.. _arduino-integerconstants:
+
+Integer Constants
+=================
+
+Integer constants are numbers used directly in a sketch, like
+``123``. By default, these numbers are treated as
+`int <http://arduino.cc/en/Reference/Int>`_'s but you can change
+this with the U and L modifiers (see below).
+
+
+
+Normally, integer constants are treated as base 10 (decimal)
+integers, but special notation (formatters) may be used to enter
+numbers in other bases.
+
+
+
+::
+
+    Base               Example    Formatter        Comment
+    
+    10 (decimal)           123    none
+    
+    2 (binary)        B1111011    leading 'B'      only works with 8 bit values (0 to 255)
+                                                   characters 0-1 valid
+    
+    8 (octal)             0173    leading "0"      characters 0-7 valid       
+    
+    16 (hexadecimal)      0x7B    leading "0x"     characters 0-9, A-F, a-f valid    
+
+
+
+**Decimal** is base 10. This is the common-sense math with which
+you are acquainted. Constants without other prefixes are assumed to
+be in decimal format.
+
+
+
+Example:
+::
+
+    101     // same as 101 decimal   ((1 * 10^2) + (0 * 10^1) + 1)
+
+**Binary** is base two. Only characters 0 and 1 are valid.
+
+
+
+Example:
+::
+
+    B101    // same as 5 decimal   ((1 * 2^2) + (0 * 2^1) + 1)
+
+The binary formatter only works on bytes (8 bits) between 0 (B0)
+and 255 (B11111111). If it is convenient to input an int (16 bits)
+in binary form you can do it a two-step procedure such as:
+
+
+
+::
+
+    myInt = (B11001100 * 256) + B10101010;    // B11001100 is the high byte
+
+
+
+**Octal** is base eight. Only characters 0 through 7 are valid.
+Octal values are indicated by the prefix "0"
+
+
+
+Example:
+
+::
+
+    0101    // same as 65 decimal   ((1 * 8^2) + (0 * 8^1) + 1) 
+
+Warning
+It is possible to generate a hard-to-find bug by (unintentionally)
+including a leading zero before a constant and having the compiler
+unintentionally interpret your constant as octal.
+**Hexadecimal (or hex)** is base sixteen. Valid characters are 0
+through 9 and letters A through F; A has the value 10, B is 11, up
+to F, which is 15. Hex values are indicated by the prefix "0x".
+Note that A-F may be syted in upper or lower case (a-f).
+
+
+
+Example:
+
+::
+
+    0x101   // same as 257 decimal   ((1 * 16^2) + (0 * 16^1) + 1)
+
+
+
+U & L formatters
+----------------
+
+By default, an integer constant is treated as an
+`int <http://arduino.cc/en/Reference/Int>`_ with the attendant
+limitations in values. To specify an integer constant with another
+data type, follow it with:
+
+
+
+
+-  a 'u' or 'U' to force the constant into an unsigned data format.
+   Example: ``33u``
+-  a 'l' or 'L' to force the constant into a long data format.
+   Example: ``100000L``
+-  a 'ul' or 'UL' to force the constant into an unsigned long
+   constant. Example: ``32767ul``
+
+
+
+
+
+See also
+--------
+
+
+-  `constants <http://arduino.cc/en/Reference/Constants>`_
+-  `#define <http://arduino.cc/en/Reference/Define>`_
+-  `byte <http://arduino.cc/en/Reference/Byte>`_
+-  `int <http://arduino.cc/en/Reference/Int>`_
+-  `unsigned int <http://arduino.cc/en/Reference/UnsignedInt>`_
+-  `long <http://arduino.cc/en/Reference/Long>`_
+-  `unsigned long <http://arduino.cc/en/Reference/UnsignedLong>`_
+
+