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Thread: array help

  1. #1
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    Unhappy array help

    I am trying to figure out ow to read integers from a user specified file in to an array. Since i don't ave any information about te file except for the fact that it is more or less a matrix, how do I get the program to read those numbers into a multidimensional array ?

  2. #2
    quad64bit's Avatar
    quad64bit is offline Moderator
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    You will HAVE to know something about the file. For example, you'll need to know what delimiters are being used, or test for several different ones; i.e. spaces, commas, periods, whatever.

    Once you know what type of delimiter is used, you can make a 2d array and then read the input line by line.
    For file input, I usually use something like the following:
    Java Code:
    BufferedReader in = new BufferedReader(new FileReader("myFile.txt"));
    String line = in.readLine();
    String[] numbersAsStrings = line.split(",");  //creates an array of strings split by the supplied delimiter, in this case a ,
    for(int i=0; i<numbersAsStrings.length; i++){
        some2DArray[row][i] = Integer.parseInt(numbersAsStrings[i]);
    That is an over-simplified example, I'm not checking for errors, and I'm only reading in 1 row. You would need to either make a nested for loop or a while loop that tests for end of file or something like that. I hope it gets you started! :D

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