Verify that a set of characters contains all the characters in a string
by identifying the position of the first character in a string of characters
that does not appear in a given set of characters.
Class
Elemental function
Argument type and attributes
STRING
must be of type character.
SET
must be of type character with the same kind type parameter as STRING.
BACK (optional)
must be of type logical.
Result type and attributes
Default integer.
Result value
Case (i): If BACK is absent or present with the value .FALSE. and
if STRING contains at least one character that is not in SET, the value of
the result is the position of the leftmost character of STRING that is not
in SET.
Case (ii): If BACK is present with the value .TRUE. and if STRING
contains at least one character that is not in SET, the value of the result
is the position of the rightmost character of STRING that is not in SET.
Case (iii): The value of the result is zero if each character in STRING
is in SET or if STRING has zero length.
Examples
Case (i): VERIFY ('ABBA', 'A') has the value 2.
Case (ii): VERIFY ('ABBA', 'A', BACK = .TRUE.) has the
value 3.
Case (iii): VERIFY ('ABBA', 'AB') has the value 0.