UMBC CS 201, Spring 02
UMBC CMSC 201 Spring '02 CSEE | 201 | 201 S'02 | lectures | news | help

De Morgan's Law

Sometimes it can be confusing to think about boolean expressions with not's and or's.

For example

If the value is not 2 or not 3 then ...
if translated literally from English, becomes :
     if ((v != 2) || (v != 3)) ...
which is ALWAYS TRUE

what we really want is:

     if ((v != 2) && (v != 3)) ...

You can always use some tautologies to simplify things.

Demorgan's law

from the meaning of not


CSEE | 201 | 201 S'02 | lectures | news | help

Thursday, 17-Jan-2002 13:52:01 EST