Thread: Organizing a text file

  1. #1
    Just a pushpin. bernt's Avatar
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    Organizing a text file

    So... I'm making a chatbot program to familiarize myself with the functions in <stdio.h>... it uses fnmatch, getc, fopen, and stuff like that... but I had a question: what's the best way to organize the data file? It holds patterns to match, like "Hello*.", and responses to those patterns, like ">>Hi.". Here's what it looks like, basically:

    Code:
    Hello*.
    >>Hi.
    How are you*?
    >>Peachy.
    *
    >>What?
    (The ">>" is just to differentiate between patterns and responses.)

    So all I have to do here is check every other line with fnmatch() and if it matches, I get the next line and display it.
    I'm not concerned with finding the best match, I can do that on my own time. Just the speed with which I find a match.

  2. #2
    and the hat of int overfl Salem's Avatar
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    Go with that.
    It's simple enough to parse, and easy enough to explain.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  3. #3
    spurious conceit MK27's Avatar
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    Quote Originally Posted by bernt View Post
    I'm not concerned with finding the best match, I can do that on my own time. Just the speed with which I find a match.
    So read the entire file into memory using an array of stucts like this one:
    Code:
    struct whatever {
           char pattern[64];
           char response[64];
    };
    Much, much faster than repeatedly reading a static file. It will also make the rest of the programming easier, etc. You could of course set these up in the code itself and not use any text file, but I think the text file is a good idea that will make the program more dynamic and easy to use/modify.

    Some OOP methods would be perfect here if you are using C++.
    C programming resources:
    GNU C Function and Macro Index -- glibc reference manual
    The C Book -- nice online learner guide
    Current ISO draft standard
    CCAN -- new CPAN like open source library repository
    3 (different) GNU debugger tutorials: #1 -- #2 -- #3
    cpwiki -- our wiki on sourceforge

  4. #4
    Just a pushpin. bernt's Avatar
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    Thanks.

    I looked at the ALICE program. They split the patterns into files (A.txt, B.txt...) based on the first letter of the input, to minimize time spent searching.

  5. #5
    spurious conceit MK27's Avatar
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    Quote Originally Posted by bernt View Post
    Thanks.

    I looked at the ALICE program. They split the patterns into files (A.txt, B.txt...) based on the first letter of the input, to minimize time spent searching.
    Leave it all in one file and then break it up when you load it:
    Code:
    struct whatever *Alist, *Blist...etc
    switch (pattern[0]) {
         case ('a'): addto(Alist, pattern, response)
    Alist would be a pointer to an array of structs, and "addto" would be a function to allocate another struct in the array + add the data to it. I guess these would ideally be linked lists -- maybe that is a bit much to tackle all at once...

    And on the other hand...
    If you are just doing this as a learning exercise, don't waste your time making up tons and tons of patterns/responses -- that is not programming, it's tedious. I think the point you should clue into here is that dealing with data in memory is much much much faster than reading it from a file. You should be able to do the struct array (forget linked lists) -- a basic task. That's learning C programming.
    Last edited by MK27; 05-15-2009 at 02:37 PM.
    C programming resources:
    GNU C Function and Macro Index -- glibc reference manual
    The C Book -- nice online learner guide
    Current ISO draft standard
    CCAN -- new CPAN like open source library repository
    3 (different) GNU debugger tutorials: #1 -- #2 -- #3
    cpwiki -- our wiki on sourceforge

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