File output location specification...

This is a discussion on File output location specification... within the C Programming forums, part of the General Programming Boards category; Hi, I am using the following code, which successfully writes a file to the location below... Code: FILE *fp = ...

  1. #1
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    File output location specification...

    Hi,
    I am using the following code, which successfully writes a file to the location below...

    Code:
    FILE *fp = fopen("/Users/me/Desktop/database456abcXa.txt", "w");
    
    if (fp != NULL)
    {
    	fprintf(fp, "Hello, world. This is a file output... Hopefully.");
    	fclose(fp);
    }
    But I would like the user to be able to specify where to save the file...
    so rather than giving it "/Users/me/Desktop/database456abcXa.txt"

    I would like to give it values (defined elsewhere), to be something more like:
    fopen( Directory1 "/" Directory2 "/database456abcXa.txt", "w");
    (you get the idea...)
    How do I do this...
    thanks!

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    Naturally, the value of Directory1 would be a string...

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    Banned master5001's Avatar
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    Exactly as you said in your example. You can fopen() directories like "~/Desktop/whatever.txt" or "C:/Documents and Settings/Me/Desktop/whatever.txt"

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    Banned master5001's Avatar
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    You can cwd to a different location to make your relative location different.

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    C++まいる!Cをこわせ! Elysia's Avatar
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    Quote Originally Posted by master5001 View Post
    You can cwd to a different location to make your relative location different.
    That usually means invoking a system command, which is unportable.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.
    For information on how to enable C++11 on your compiler, look here.
    よく聞くがいい!私は天才だからね! ^_^

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    Yes, but what if rather than predefining the location such as: "~/Desktop/whatever.txt"
    I want the program to first take user input, assigned to variable INPUT, and then write the file to:
    "~/INPUT/whatever.txt"

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    And I would prefer to do this without a system command such as cwd...

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    C++まいる!Cをこわせ! Elysia's Avatar
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    Ask the user for the path as where to store it. Save that in a string buffer. Pass string buffer to fopen.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.
    For information on how to enable C++11 on your compiler, look here.
    よく聞くがいい!私は天才だからね! ^_^

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    Banned master5001's Avatar
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    Well I mean use your operating system's method for changing the current working directory. I may overly assume basic knowledge of computers when making such comments.

    Windows. In linux there are a couple methods that come to mind. Or I suppose you can use system() to do your bidding, but that is nasty.

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    Banned master5001's Avatar
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    Why not use sprintf()?

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    That's what I want to do...
    what would the formatting of that look like in terms of:
    "FILE *fp = fopen("/Users/Desktop/database.txt", "w");

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    master5001, i know how to change directories, but is it not possible to do with a:
    Take user input, assigned to variable INPUT, and then write the file to:
    "~/INPUT/whatever.txt"
    formatting?

  13. #13
    Banned master5001's Avatar
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    You're killing me, Smalls.

    Example:
    Code:
    size_t get_user_file_path(char *buffer, size_t size, const char *user)
    {
      return snprintf(buffer, size, "/%s/Desktop/database.txt", user);
    }

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    What?
    Sorry, new to this...

  15. #15
    and the Hat of Guessing tabstop's Avatar
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    Quote Originally Posted by hebali View Post
    master5001, i know how to change directories, but is it not possible to do with a:
    Take user input, assigned to variable INPUT, and then write the file to:
    "~/INPUT/whatever.txt"
    formatting?
    Since that's what we've been telling you to do, my guess is that it is possible. Use sprintf (or even snprintf, below) to create your filename string. sprintf works just the same as printf, in terms of the format, but instead of writing to the screen it writes to a char array.

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