Skip to main content
ICT
A14 - Boolean Algebra and Loop Boundaries
 
Main Previous Next
Title Page >  
Summary >  
Lesson A1 >  
Lesson A2 >  
Lesson A3 >  
Lesson A4 >  
Lesson A5 >  
Lesson A6 >  
Lesson A7 >  
Lesson A8 >  
Lesson A9 >  
Lesson A10 >  
Lesson A11 >  
Lesson A12 >  
Lesson A13 >  
Lesson A14 >  
Lesson A15 >  
Lesson A16 >  
Lesson A17 >  
Lesson A18 >  
Lesson A19 >  
Lesson A20 >  
Lesson A21 >  
Lesson A22 >  
Lesson AB23 >  
Lesson AB24 >  
Lesson AB25 >  
Lesson AB26 >  
Lesson AB27 >  
Lesson AB28 >  
Lesson AB29 >  
Lesson AB30 >  
Lesson AB31 >  
Lesson AB32 >  
Lesson AB33 >  
Vocabulary >  
 

A. Negations of Boolean Assertions page 3 of 7

  1. A Boolean assertion is simply an expression that results in a true or false answer. For example,

    a > 5
    0 == b
    a <= b

    are all statements that will result in a true or false answer.

  2. To negate a Boolean assertion means to write the opposite of a given Boolean assertion. For example, given the following Boolean assertions noted as A, the corresponding negated statements are the result of applying the ! operator to A.

    A
    !A
    5 == x
    5 != x
    x < 5
    x >= 5
    x >= 5
    x < 5

  3. Notice that negations of Boolean assertions can be used to re-write code. For example:

if (!(x < 5))
   // do something...

can be rewritten as

if (x >= 5)
   // do something ...

This is important because we understand positive statements much more easily than statements that contain one or more !s.

 

Main Previous Next
Contact
 © ICT 2006, All Rights Reserved.