Reading a file to variables

This is a discussion on Reading a file to variables within the C++ Programming forums, part of the General Programming Boards category; Hello. I want to make a program that can read a normal txt file and set certain lines to certain ...

  1. #1
    BigBadApe
    Guest

    Question Reading a file to variables

    Hello.
    I want to make a program that can read a normal txt file and set certain lines to certain variables...

    heres an example, say i have,
    int a, b, c, d;
    and then the file looks like this...

    this is my file
    b: 2
    and other stuff in between the values i want.
    d: 8
    and so on
    a: 1
    so i have a pretty much jumbled file
    c: 9

    and then i want my code to go through the file and set variables according to the file, i.e b=2 etc... i was thinking of using strcmp to search the file a: b: etc..., but then how could i put the value thats directly after the target into the variable

  2. #2
    Just because ygfperson's Avatar
    Join Date
    Jan 2002
    Posts
    2,493
    use seekp (or seekg, i forget which one) if you're using an fstream. use google for documentation on those.

  3. #3
    Registered User Dual-Catfish's Avatar
    Join Date
    Sep 2001
    Posts
    802
    Code:
    char numeric[] =  "1234567890";
    
    int a, b, c, d;
    char buf[20];
    
    ifstream fin("filename.txt");
    while (!ifstream.eof())
    {
          ifstream.getline(buf, 19, '\n');
    
          char *found = strpbrk(buf, numeric);
          int extractedDigit = atoi(found);
    
          switch(buf[0])
          {
                case 'a': a = extractedDigit;
                break;
                // ...
          }
    }
    You could use something like that. (Hell, I hope that works) Although, with a little added complexity, i'm pretty sure you could trash the switch statement for a token pasting macro.

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