'''ON...GOSUB''' is a control-flow statement that branches to a line or label in a list depending on a numerical expression.


{{PageSyntax}}
:: '''ON''' ''numerical-expression'' '''GOSUB''' ''lineornumber[,lineornumber][,...]''


* The ''numerical-expression represents'' the ''line'' or ''label'' that it should branch to, 1 branches to the first line or label, 2 branches to the second, etc.
* In QB 4.5 the list can contain a maximum of 60 line numbers or labels, while QB64 has no limit.
* The procedure must be used after the number value is determined or in a loop to monitor current user events. 
* [[RETURN]] returns to the next code statement after the ON...GOSUB statement. [[END]] or [[SYSTEM]] can be used to end program.
* '''Note:''' [[SELECT CASE]] provides a much more convenient way of doing this task.


''Example:''
{{CodeStart}} '' ''
{{Cl|CLS}}
a = 2
''ON'' a '''GOSUB''' hello, hereweare, 143
{{Cl|PRINT}} "Also notice the RETURN statement that can be used with GOSUB!"
{{Cl|END}}

hello:
{{Cl|PRINT}} "Hello, with a = 1 you get to see this!"
{{Cl|END}}

hereweare:
{{Cl|PRINT}} "with a = 2 here we are...return to line after ON."
{{Cl|RETURN}}

143
{{Cl|PRINT}} "Line 143, with a = 3 you get to see this!"
{{Cl|END}} '' ''
{{CodeEnd}}
{{OutputStart}}
with a = 2 here we are...return to line after ON.
Also notice the RETURN statement that can be used with GOSUB!
{{OutputEnd}}

:''Explanation:'' Since a equals to 2 it goes to the second item in the list (hereweare) and branches the program to there. Try changing 'a' to 1 or 3!


''See also:'' 
* [[ON...GOTO]]
* [[GOSUB]], [[GOTO]] 
* [[SELECT CASE]], [[RETURN]]


{{PageNavigation}}