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2.8.20 Requesting Input

Mathematica usually works by taking whatever input you give, and then processing it. Sometimes, however, you may want to have a program you write explicitly request more input. You can do this using Input and InputString.

Interactive input.

Exactly how Input and InputString work depends on the computer system and Mathematica interface you are using. With a text-based interface, they typically just wait for standard input, terminated with a newline. With a notebook interface, however, they typically get the front end to put up a "dialog box", in which the user can enter input.
In general, Input is intended for reading complete Mathematica expressions. InputString, on the other hand, is for reading arbitrary strings.