Thread: ideas for render a string to a variable

  1. #1
    Registered User
    Join Date
    Mar 2008

    ideas for render a string to a variable

    I'd like to teach the world to c

  2. #2
    C++ Witch laserlight's Avatar
    Join Date
    Oct 2003
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  3. #3
    Registered User
    Join Date
    Mar 2008
    ehem, cough, sorry ahd some problems there with awriting a post thinking I was logged in, but turns out I wasn't, so I lost it.

    Anyhow, keeping with the subject, I'd like to read in some variable values from a setting text file, which goes like so:
    varname = value
    fscanf(filein, "%s = %i", varname, &value);
    would *roughly* be what I'd do ...

    If the order of the variables names is observed, and known to the program the job is not too difficult. But if not - and it would be more robust - the program needs to recognise the varname is the correct. strcmp() would be the way here and then a conditional assigning.

    Is there a more direct way? JUst looking for hints. I apologise for the poor wording.Please understand it's the second time I write this post.

    Thanks in advance. Cheers.

  4. #4
    Join Date
    Oct 2007
    Inside my computer
    So I take it that if it says "a = 0", then the variable a should be assigned 0?
    If so, then I suggest you use a map. There is no standard map in C, however, so you may need to google a bit to find a good one.
    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.

  5. #5
    Registered User
    Join Date
    Oct 2008
    Still not sure what you mean, need to explain by giving a clearer example.

  6. #6
    Registered User
    Join Date
    Jan 2010
    I think what he means is if having a config file like for example
    Name = My Name
    Age = 123
    DecimalVar = 3.3
    he wants to parse the file and use the rvalue in his code by looking up the lvalue. If so then any implementation of a linked list should do, and you could do something like
    struct Variable
        const char* Name;
        void* Data;
        int VariableType;
        struct Variable* next;
    struct Variable* list = NULL;
    ParseConfigFile("filename.txt", &list);
    const char* name = GetStringVar(list, "Name");
    int age = GetIntVar(list, "Age");
    float floatVar = GetFloatVar(list, "DecimalVar");
    SetStringVar(list, "NewStringVar", "Hello World!");
    SaveConfigFile("filename.txt", list);

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