Open Watcom FORTRAN 77 Language Reference

FORTRAN Statements
2.83 Block WHILE Statement
WHILE (e) DO
[: block-label]
where:
e
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.
The block WHILE statement is used in conjunction with the structured END WHILE or UNTIL statement.
The block WHILE statement marks the beginning of a sequence of statements which are to be repeated.
The END WHILE or UNTIL statement marks the end of the WHILE-block. The WHILE-block is executed
while the logical expression of the WHILE statement has a true value or until control is transferred out of
the WHILE-block.
Example:
Example:
X = 1.0
WHILE( X .LT. 100 )DO
PRINT *, X, SQRT( X )
X = X + 1.0
END WHILE
I = 1
WHILE( I .LT. 100 )DO
J = 4 * I * I
K = 3 * I
PRINT *, ’4x**2 + 3x + 6 = ’, J + K + 6
I = I + 1
UNTIL( ( J + K + 6 ) .GT. 100 )
END
An optional block label may be specified with the WHILE statement.
For more information, see the chapter entitled "Program Structure Control Statements" on page 193.
Block WHILE Statement 145