'''GOSUB''' sends the program to a sub program that uses a line number or label.
{{PageSyntax}}
:: GOSUB label
* Label is any [[line number]] or line label designated with a colon after it. Don't use the colon in the call.
* [[RETURN]] at the end of the procedure returns to the next code after the original call. [[END]] or [[SYSTEM]] can also be used to end program.
* A procedure loop may be used to return automatically instead of using return.
* GOSUB and GOTO can be used '''within''' [[SUB]] or [[FUNCTION]] procedures, but cannot refer to a label not in the procedure itself.
* '''Note:''' Too many GOSUBs without a [[RETURN]] can eventually cause "Out of Stack Errors" in Qbasic as each GOSUB uses memory to store the location to return to. Each [[RETURN]] frees the memory of the GOSUB it returns to.
{{Cl|IF...THEN|IF}} a = 1 {{Cl|THEN}} {{Cl|GOSUB}} here: {{Cl|PRINT}} "It returned to IF a = 1": {{Cl|END}}
{{Cl|IF...THEN|IF}} a = 2 {{Cl|THEN}} {{Cl|GOSUB}} there: {{Cl|PRINT}} "It returned to IF a = 2": {{Cl|RETURN}}
here:
{{Cl|PRINT}} "It went here."
{{Cl|GOTO}} start
there:
{{Cl|PRINT}} "It went there."
{{Cl|RETURN}}
{{CodeEnd}}
{{small|Code by Cyperium}}
{{OutputStart}}
It went here.
It went there.
It returned to IF a = 2
It returned to IF a = 1
{{OutputEnd}}
''Explanation:'' When a = 1 it uses GOSUB to go to "here:", then it uses GOTO to go back to "start:". a is increased by one so when a = 2 it uses GOSUB to go to "there:", and uses RETURN to go the last GOSUB (which is on the IF a = 2 line), it then encounters another RETURN which makes it return to the first GOSUB call we used on the IF a = 1 line.