This is documentation for Mathematica 8, which was
based on an earlier version of the Wolfram Language.
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Input

Input
interactively reads in one Mathematica expression.
Input[prompt]
requests input, displaying prompt as a "prompt".
Input
in a notebook front end uses init as the initial contents of the input field.
  • Input returns the expression it reads.
  • The operation of Input may vary from one computer system to another. When a Mathematica front end is used, Input typically works through a dialog box.
  • When no front end is used, Input reads from standard input.
  • If the standard input is a file, then Input returns EndOfFile if you try to read past the end of the file.
  • On systems with textual input, Input uses as a prompt.
  • When Input is evaluated, Mathematica stops until the input has been read.
  • With a notebook front end, Input by default puts up a dialog window with a standard appearance.
  • The prompt given can be text, graphics or any expression.
  • Input by default puts up a dialog in the middle of the main display screen. Explicit settings for WindowMargins override this.
  • The option FieldSize can be used to specify the size of the field used for input.
Get an input expression and square it:
Request input of a function to plot:
Get an input expression and square it:
In[1]:=
Click for copyable input
Out[1]=
 
Request input of a function to plot:
In[1]:=
Click for copyable input
Out[1]=
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