A truth table shows how a logical expression is evaluated. This is the truth table for a logical and:
&& |
true |
false |
true |
true |
false |
false |
false |
false |
The first column represents the first term in the logical expression, the first row represents the second term. The intersection represents the result. So:
This is a truth table for a logical or:
|| |
true |
false |
true |
true |
true |
false |
true |
false |
This is a truth table for a logical eor (exclusive or):
^ |
true |
false |
true |
false |
true |
false |
true |
false |
This is a truth table for a logical not (also called logical negation):
!true |
false |
!false |
true |
When writing your logical expressions, it is a good idea to make them as simple as possible and try to use positive logic rather than negative. For instance, the logical expression (!(x > 0)) can be re-written without the not as (x <= 0).