6.1 Program Input
  BASIC programs receive data in the following ways:

  .
        You can enter data interactively while the program
        runs. You do this with the INPUT, INPUT LINE, and
        LINPUT statements.
  .
        If you know all the information your program will re-
        quire, you can enter it as you write the program. You do
        this with the READ, DATA, and RESTORE statements, or
        you can name constants with the known values.
  .
        You can read data from files outside the program. You do
        this with the INPUT #, INPUT LINE #, and LINPUT #
        statements.

  The following sections describe how to use these statements in
  detail.