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Loops in constructor

  1. Jun 21, 2008 #1

    I'm experimenting with classes in C++. It works fine for now, but there is something I can't find an explanation for. I tried to develop a 'matrix' class, and I overloaded some operators in order to define addition or multiplication for matrices. This works like a charm, except for the part where I make a default constructor to initialize my matrix.

    In order to do this, I first thought about doing a double loop to initialize all the values in the matrix. In my class CMatrix, the fragment of code is:

    Code (Text):
        CMatrix () {   
            for (int i = 0; i < ROW; i++){
                for (int j = 0; i < COL; j++){
                    matrix[i][j] = 0;
    Note: that's how I defined ROW and COL:

    #define ROW 3
    #define COL 3

    However, it doesn't work. The compilation is fine, but at some point when the program is executed, Visual Express opens a windows where it is written:

    'Violation of access at 0x00030ffc, etc.' (I can't translate everything, I have the french version of the software, but there is nothing else important to say.)

    Since my matrices are 3x3, I tried to initialize all the values by 'brute force':

    Code (Text):
    CMatrix () {   
        matrix[0][0] = 0;
        matrix[1][0] = 0;
        matrix[2][0] = 0;
        matrix[0][1] = 0;
        matrix[1][1] = 0;
        matrix[2][1] = 0;
        matrix[0][2] = 0;
        matrix[1][2] = 0;
        matrix[2][2] = 0;
    And it works! I don't see any mistakes in my loops (and VE would have found them). So, is there something I am not allowed to do?

    Thank you!
    Last edited: Jun 21, 2008
  2. jcsd
  3. Jun 21, 2008 #2
    Woops, that's the wrong sub-forum. Could somebody move this thread and delete this message ? Thanks.
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