Open Watcom FORTRAN 77 Language Reference

FORTRAN Statements
2.52 Block IF Statement
There are two forms of the block IF statement. The second is a Open Watcom FORTRAN 77 extension.
2.52.1 Standard Block IF Statement
IF (e) THEN
where:
e
is a logical expression.
The block IF statement is used in conjunction with the ELSE IF, ELSE, and END IF statements.
Example:
IF( A .LT. B )THEN
PRINT *, ’A < B’
END IF
For more information, see the chapter entitled "Program Structure Control Statements" on page 193.
2.52.2 Extended Block IF Statement
IF (e) THEN
[: block-label]
where:
e
block-label
is a logical expression or integer arithmetic expression, in which case the result
of the integer expression is compared for inequality to the integer value 0.
is an optional block label.
This form of the block IF statement is an extension to the FORTRAN 77 language. It is identical to the
standard form of the block IF statement with the exception that an integer arithmetic expression and an
optional block label are permitted.
Example:
Block IF Statement 87