From QB64 Wiki
ELSEIF is used in a block IF...THEN statement to offer an alternative condition.
- ELSEIF statements REQUIRE a separate code block line with THEN for each alternative condition.
- There can be more than one ELSE IF statement in a single-line IF statement.
- If there is only ONE possible alternative condition(such as 0 or NOT 0), then use ELSE instead.
- If the comparisons are based on multiple conditions being true, it may require many ELSEIF comparisons. ELSE could help cover some of those conditions.
- You can use SELECT CASE when IF blocks have a long list of alterative ELSEIF conditions.
|<||Less than||IF a < b THEN|
|>||Greater than||IF a > b THEN|
|=||Equal||IF a = b THEN|
|<=||Less than or equal||IF a <= b THEN|
|>=||Greater than or equal||IF a >= b THEN|
|<>||NOT equal||IF a <> b THEN|
Example 1: IF statement using ELSE IF in one statement line.
IF x = 100 THEN COLOR 10: PRINT x ELSE IF x > 100 THEN COLOR 12: PRINT x ELSE PRINT "< 100"
Example 2: IF statement block
IF x = 100 THEN ' must place ANY code on next line! COLOR 10: PRINT x ELSEIF x > 100 THEN COLOR 12: PRINT x ELSE : PRINT "< 100" END IF