ELSEIF is just this:
IF a% = 3 THEN
PRINT "Three"
ELSE
IF a%=5 THEN
PRINT "Five"
ELSE
PRINT "Not five nor three"
END IF
END IF
translates to... (faster to write)
IF a%=3 THEN
PRINT "Three"
ELSEIF a%=5 THEN
PRINT "Five"
ELSE
PRINT "Not five nor three"
END IF
I don't see why it is evil, but there is a better form:
SELECT CASE a%
CASE 3:
PRINT "Three"
CASE 5:
PRINT "Five"
CASE ELSE:
PRINT "Not five nor three"
END SELECT
You'll only notice the speed increase if you need to evaluate things in a long loop (for example, in a game loop).