Expressions with more than two Boolean operators

 

It’s possible to construct logical expressions with more than two Boolean operators just as we can have an arithmetic expressions with multiple operators.  In both cases, we need to worry about the order in which operators are evaluated (precedence rules).  For Boolean operators, negation (!) has highest precedence, followed by the logical and (&&), and finally the logical or (||).  Consider the following expression with three relational statements and their truth values below:

 

      stmt1  ||  stmt2  &&  stmt3

        T          F          F

 

The expression evaluates to true since && is evaluated first (resulting in false), and then the || operator (Beware: evaluating from left two right without taking operator precedence into account would have yielded false).  When in doubt about precedence, it’s a good idea to use parentheses.