variable

This is a discussion on variable within the C++ Programming forums, part of the General Programming Boards category; I was trying to get my program to work the following way from the terminal (command prompt): a.out 20 < ...

  1. #1
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    Question variable

    I was trying to get my program to work the following way from the terminal (command prompt):

    a.out 20 < document.doc

    where the value "20" (or whatever is typed) is used as a variable in the compiled program's a.out file (program.cpp). I've tried a bunch of different ways to no avail... Help?
    Last edited by bond_006; 04-11-2010 at 09:10 PM.

  2. #2
    and the Hat of Guessing tabstop's Avatar
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    I don't think that makes any sense as you have it typed. You have a compiled program, yes? Does it take a command-line argument? If so, just type it: "a.out 20". If it doesn't take a command-line argument, then you've already lost ... unless it takes input from the user, in which case you need a file that says 20 in it that you can use to redirect (although just waiting to type "20" at the prompt doesn't seem like such a burden).

  3. #3
    and the hat of int overfl Salem's Avatar
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    If the program is expecting an integer (on stdin), followed by a document (also on stdin), then do this:
    Code:
    ( echo "20" ; cat document.doc ) | a.out
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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    Salem's bash code is probably not what you want, in all likely hood.

    How does the program read in 20 and the doc file?
    It is too clear and so it is hard to see.
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