A condition or logical expression is an expression that can
only take the values false or true.
A relational expression is constructed from arithmetic expressions
combined by the relational operators less than, greater than, equal, not
equal, greater than or equal and less than or equal.
A logical expression is constructed from relational expressions by use of
the logical operators not, and and or.
C++ evaluates only as many operands as necessary to find the
value of a logical expression involving and or or.
