Please Whitelist This Site?
I know everyone hates ads. But please understand that I am providing premium content for free that takes hundreds of hours of time to research and write. I don't want to go to a pay-only model like some sites, but when more and more people block ads, I end up working for free. And I have a family to support, just like you. :)
If you like The TCP/IP Guide, please consider the download version. It's priced very economically and you can read all of it in a convenient format without ads.
If you want to use this site for free, I'd be grateful if you could add the site to the whitelist for Adblock. To do so, just open the Adblock menu and select "Disable on tcpipguide.com". Or go to the Tools menu and select "Adblock Plus Preferences...". Then click "Add Filter..." at the bottom, and add this string: "@@||tcpipguide.com^$document". Then just click OK.
Thanks for your understanding!
Sincerely, Charles Kozierok
Author and Publisher, The TCP/IP Guide
NOTE: Using software to mass-download the site degrades the server and is prohibited.
If you want to read The TCP/IP Guide offline, please consider licensing it. Thank you.
Boolean Logic and Logical Functions
(Page 3 of 3)
Combining Boolean Functions to Create Boolean Expressions
The functions described above can
also be combined in arbitrary ways to produce more complex logical conditions.
Boolean logic expressions are used in many different contexts in the
computing field. A common place that most people use them is in a World
Wide Web search engine. For example, if you enter cheese AND (cheddar
OR swiss) NOT wisconsin into a search engine, the program will
return pages that contain the word cheese that also contain
the word cheddar or swiss (or both), but that
do not contain the word wisconsin.
(Sorry, Wisconsinite cheese loversbut
I live in Vermont! J)
Boolean functions are the building
blocks of much of the circuitry within computer hardware. The functions
are implemented as tiny gates that are designed to allow electrical
energy to flow to the output only based on certain combinations of inputs
as described by the truth tables for functions like NOT, AND,
OR and others. In networking, boolean logic is important for
describing certain conditions and functions in the operation of networks.
Boolean functions are also very important because they are used to set,
clear and mask strings of binary digits, which we will explore in the
Key Concept: Boolean logic is a system that uses boolean functions to produce outputs based on varying conditions in their input data. The most common boolean functions are NOT, which produces as output the opposite of its input; AND, which is true (1) only if all of its inputs are true (1); OR, which is true if any of its inputs is true; and XOR, which is true only if exactly one of its inputs is true (or put another way, if the inputs are different). These functions can be used in boolean logic expressions that represent conditional states for making decisions, and can also be used for bit manipulation.
|If you find The TCP/IP Guide useful, please consider making a small Paypal donation to help the site, using one of the buttons below. You can also donate a custom amount using the far right button (not less than $1 please, or PayPal gets most/all of your money!) In lieu of a larger donation, you may wish to consider purchasing a download license of The TCP/IP Guide. Thanks for your support!|
Table Of Contents - Contact Us
The TCP/IP Guide (http://www.TCPIPGuide.com)
Version 3.0 - Version Date: September 20, 2005
© Copyright 2001-2005 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.