GOSUB
=====

Function
--------

**GOSUB** causes execution to jump to a Basic subroutine located
elsewhere in the applications program.

Syntax
------

GOSUB line number

GOSUB numeric expression

Examples
--------

::

   GOSUB 150

causes program execution to jump to a subroutine located at 150.

The argument can also be an argument or expression, for example:

::

   GOSUB SI

or

::

   GOSUB SI+100*A

This is illustrated by the program sequence:

::

   10 INPUT A
   20 SI=1000
   30 GOSUB SI+100*A
   40 STOP
   1000 PRINT "THIS IS SUBROUTINE 1"
   1010 RETURN
   1100 PRINT "THIS IS SUBROUTINE 2"
   1110 RETURN
   etc.

If the number 0 is entered in line 10, the program will perform
subroutine 1. Input of the number 1 will cause subroutine 2 to be
executed.

Remarks
-------

A subroutine must always be terminated by a :doc:`return`
statement. Program execution then continues from the statement
immediately after the GOSUB. GOSUB always requires a line number as an
argument.