Logical expressions can be used in logical assignment statements, but are most commonly encountered in IF statements where there is a compound condition, for example:
IF(AGE .GE. 60 .OR. (STATUS .EQ. 'WIDOW' .AND.
$ NCHILD .GT. 0) THEN
This combines the values of three relational expressions, two of
them comparing arithmetic values, the other character values. The
logical operators such as .AND. and .OR. also need decimal
points
at either end to distinguish them from symbolic names. The .OR.
operator performs an inclusive or, the exclusive or operator is
called .NEQV..