Home Accessibility Courses Twitter The Mouth Facebook Resources Site Map About Us Contact
 
Python and Tcl - public course schedule [here]
Private courses on your site - see [here]
Please ask about maintenance training for Perl, PHP, Lua, etc
 
Cardinal numbers and magic numbers

A cardinal number, in computing terms, is a term that's sometimes used to refer to a fixed condition - in other words, you might call a function with one parameter should of the usual number, and the final value will be assigned a cardinal number that can't occur there in reality. For example, you might call a function into which you input the number of children a person has, and if no value is entered the value could be set to a cardinal 999 that's checked for by the code. Should work, shouldn't it? After all - no-one could have 999 children. And it would work fine until the local headmaster, with a role of 1 short of 100 students, runs it on his hordes

A magic number is formed of certain bytes at the start of a file which signify the content type in the file. For example, the first three bytes of a .gif image file are GIF. The Unix and Linux file command uses magic numbers to identify content type.
(written 2006-12-14, updated 2006-12-21)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
A101 - Web Application Deployment - Linux -An Introduction For Users
  [3819] Packing a tar, jar or war file - best practise - (2012-07-26)
  [3791] The Kernel, Shells and Daemons. Greek Gods in computing - (2012-07-01)
  [3256] Displaying a directory or file system tree - Linux - (2011-04-22)
  [3179] Oops - I typed ci not vi, and have lost my file ... - (2011-02-21)
  [2831] Recording (a macro) in vi - (2010-06-27)
  [2636] Linux - useful tips including history and file name completion - (2010-02-15)
  [2494] Making Linux Politically correct - (2009-11-06)
  [2479] Accidentally typed ci rather than vi? - (2009-10-27)
  [2300] What does x on a linux directory mean? - (2009-07-21)
  [2299] How much space does my directory take - Linux - (2009-07-20)
  [2203] Always use su with minus. And where do programs come from? - (2009-05-27)
  [2201] Running straight from the jar, but not from a tar - (2009-05-26)
  [1904] Ruby, Perl, Linux, MySQL - some training notes - (2008-11-23)
  [1902] sstrwxrwxrwx - Unix and Linux file permissions - (2008-11-23)
  [1897] Keeping on an even keel - (2008-11-21)
  [1893] Some Linux and Unix tips - (2008-11-18)
  [1803] FTP passive mode - a sometimes cure for upload hangs - (2008-09-20)
  [1764] Yank and Push - copy and move in vi - (2008-08-21)
  [1651] ls command - favourite options - (2008-05-23)
  [1527] Selecting file names in a shell - one word or another - (2008-02-02)
  [1438] Copy and paste / cut and paste and other vi techniques - (2007-11-20)
  [1408] Wireless hotel tips - FTP and Skype connections failing - (2007-10-26)
  [1366] awk - a powerful data extraction and manipulation tool - (2007-09-25)
  [1288] Linux run states, shell special commands, and directory structures - (2007-08-03)
  [1287] Work and play at Well House Manor - Football and Shell Shortcuts - (2007-08-02)
  [1259] Where am I and how did I get here? - (2007-07-05)
  [1068] ls -l report, Linux / Unix - types and permssions - (2007-02-06)
  [1013] Copy multiple files - confusing error message from cp - (2006-12-30)
  [1012] Moving files between Windows / DOS and Linux / Unix - (2006-12-30)
  [749] Cottage industry or production line data handling methods - (2006-06-07)
  [711] THE home directory or MY home directory - (2006-05-06)
  [710] Linux training Glasgow, Python programming course Dundee - (2006-05-05)
  [703] Copying files and preserving ownership - (2006-04-28)
  [679] More or less on the edge of the page - (2006-04-11)
  [659] Web Application Components - (2006-03-28)
  [593] Finding where the disc space has gone - (2006-02-06)
  [431] File permissions of Linux and Unix systems - (2005-08-31)
  [430] Linux commands - some basics - (2005-08-31)
  [249] An easy way out - (2005-03-17)
  [152] Aladdin, or careful what you wish. - (2004-12-15)
  [74] pushd and popd - (2004-10-05)
  [73] vi - full circle - (2004-10-04)


Back to
Blessing in Perl / Member variable in Ruby
Previous and next
or
Horse's mouth home
Forward to
Equality in Ruby - == eql? and equal?
Some other Articles
You should think you're first in a hotel room
Ruby v Perl - interpollating variables
puts - opposite of chomp in Ruby
Equality in Ruby - == eql? and equal?
Cardinal numbers and magic numbers
Blessing in Perl / Member variable in Ruby
Notes from the white board
Finalist reception - Wiltshire Business of the Year
Street Scene
Empty seats, Nodding Donkeys and buses
4759 posts, page by page
Link to page ... 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96 at 50 posts per page


This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

Link to Ezine home page (for reading).
Link to Blogging home page (to add comments).

You can Add a comment or ranking to this page

© WELL HOUSE CONSULTANTS LTD., 2019: 404 The Spa • Melksham, Wiltshire • United Kingdom • SN12 6QL
PH: 01225 708225 • EMAIL: info@wellho.net • WEB: http://www.wellho.net • SKYPE: wellho

PAGE: http://www.wellho.net/mouth/984_Card ... mbers.html • PAGE BUILT: Sat May 27 16:49:10 2017 • BUILD SYSTEM: WomanWithCat