UMBC CS 201, Spring 06
UMBC CMSC 201
Spring '06
CSEE | 201 | 201 S'06 | 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.

De Morgan's law

from the meaning of not

CSEE | 201 | 201 S'06 | lectures | news | help

Monday, 23-Jan-2006 09:13:30 EST