Boolean Operators

Boolean operators are those that deal with true and false values. For the purpose of this course, you should understand the use of NOT, AND and OR.

NOT ( ! )

The simplest boolean operator, NOT inverts the value supplied. The truth table for a NOT gate is shown below.

INPUT	OUTPUT
true	false
false	true

AND ( && )

A logical AND returns false unless ALL inputs are true. The truth table for a two-input logical AND is displayed below.

INPUT A	INPUT B	OUTPUT
false	false	false
false	true	false
true	false	false
true	true	true

OR ( || )

A logical OR returns false only if all inputs are false. If one or more of the inputs are true, then the output is true. The truth table is below.

INPUT A	INPUT B	OUTPUT
false	false	false
false	true	true
true	false	true
true	true	true