ON...GOSUB               Branch to nth Item in Subroutine List

 ON n GOSUB {linenum | linelabel}, [,{linenum | linelabel}]...

    Causes Turbo Basic to branch to one of a list of subroutine starting
    lines.

           n    A numeric variable in the range 0 to 255. Upon execution
                of the ON...GOSUB statement, Turbo Basic branches to the
                nth item in the list of line numbers that follows the
                keyword GOSUB.

     linenum    The first line number of a subroutine.

   linelabel    A label identifying the first line of a subroutine.

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      Notes:    If n is 0 or larger than the number of items in the line
                list, Turbo Basic continues with the next executable
                statement.

                The SELECT and IF block statements are more flexible
                versions of multi-way branching.