statement condition.
elseif is used with IF. The after the elseif are
executed if the is true and all the preceding IF and
elseif are false. An expression is considered true if
the real part has all non-zero elements.

elseif does not need a matching , IF does.

The general form of the IF statement is
IF expression
statements
elseif expression
statements
ELSE
statements
END

See also if, else, end.