Editing Hexadecimal (section)

===Hexadecimal exponential notation===
Just as decimal numbers can be represented in [[exponential notation]], so too can hexadecimal numbers.  [[P notation]] uses the letter ''P'' (or ''p'', for "power"), whereas ''E'' (or ''e'') serves a similar purpose in decimal [[E notation]]. The number after the ''P'' is ''decimal'' and represents the ''binary'' exponent. Increasing the exponent by 1 multiplies by 2, not 16: {{mono|1=20p0 = 10p1 = 8p2 = 4p3 = 2p4 = 1p5}}. Usually, the number is normalized so that the hexadecimal digits start with {{mono|1.}} (zero is usually {{mono|0}} with no ''P'').

Example: {{mono|1.3DEp42}} represents {{math|1.3DE<sub>16</sub> × 2<sup>42<sub>10</sub></sup>}}.

P notation is required by the [[IEEE 754-2008]] binary floating-point standard and can be used for floating-point literals in the [[C99]] edition of the [[C (programming language)|C programming language]].<ref>{{cite web |url=http://www.iso.org/iso/iso_catalogue/catalogue_ics/catalogue_detail_ics.htm?csnumber=29237 |title=ISO/IEC 9899:1999 – Programming languages – C |publisher=Iso.org |website=ISO |date=2011-12-08 |access-date=2014-04-08 |archive-date=2016-10-10  |archive-url=https://web.archive.org/web/20161010112929/http://www.iso.org/iso/iso_catalogue/catalogue_ics/catalogue_detail_ics.htm?csnumber=29237 |url-status=live }}</ref>
Using the ''%a'' or ''%A'' conversion specifiers, this notation can be produced by implementations of the ''[[printf]]'' family of functions following the C99 specification<ref name="Rationale_2003_C">{{cite web |title=Rationale for International Standard – Programming Languages – C |version=5.10 |date=April 2003 |pages=52, 153–154, 159 |url=http://www.open-std.org/jtc1/sc22/wg14/www/C99RationaleV5.10.pdf |website=Open Standards |access-date=2010-10-17 |url-status=live |archive-url=https://web.archive.org/web/20160606072228/http://www.open-std.org/jtc1/sc22/wg14/www/C99RationaleV5.10.pdf |archive-date=2016-06-06}}</ref> and
[[Single UNIX Specification|Single Unix Specification]] (IEEE Std 1003.1) [[POSIX]] standard.<ref name="printf_2013">{{cite web |title=dprintf, fprintf, printf, snprintf, sprintf – print formatted output |work=The Open Group Base Specifications |edition=Issue 7, IEEE Std 1003.1, 2013 |date=2013 |orig-year=2001 |author=The IEEE and The Open Group |url=http://pubs.opengroup.org/onlinepubs/9699919799/functions/printf.html |access-date=2016-06-21 |url-status=live |archive-url=https://web.archive.org/web/20160621211105/http://pubs.opengroup.org/onlinepubs/9699919799/functions/printf.html |archive-date=2016-06-21}}</ref>