diagmatr

Matrix2x2 Matrix2x2::stringchange()
{
    Matrix2x2 a;
    a.matr[0][0] = matr[1][0];
    a.matr[0][1] = matr[1][1];
    a.matr[1][0] = matr[0][0];
    a.matr[1][1] = matr[0][1];
    return a;
}
Matrix2x2 Matrix2x2::equivalentDiagonal()
{
    Matrix2x2 a;
    if (matr[0][0] == 0 && matr[1][1] == 0)
    {
        a = this->stringchange(); //просто меняем строки местами
    }
    else
    {
        if (matr[0][0] == 0 && matr[0][1] != 0)
        {
            for (i = 0; i < 2; i++)
                for (j = 0; j < 2; j++)
                    a.matr[i][j] = matr[i][j];
            a.matr[1][1] = matr[0][1] * (-matr[1][1] / matr[0][1]) + matr[1][1];
            a = a.stringchange();
        }
        else
        {
            if (matr[1][1] == 0 && matr[1][0] != 0)
            {
                for (i = 0; i < 2; i++)
                    for (j = 0; j < 2; j++)
                        a.matr[i][j] = matr[i][j];
                a.matr[0][0] = matr[0][0] + (-matr[0][0] / matr[1][0]) * matr[1][0];
                a = a.stringchange();
            }
            else
            {
                a.matr[1][0] = matr[0][0] * (-matr[1][0] / matr[0][0]) + matr[1][0];
                a.matr[1][1] = matr[0][1] * (-matr[1][0] / matr[0][0]) + matr[1][1];
                a.matr[0][0] = matr[0][0];
                a.matr[0][1] = matr[0][1] + (-matr[0][1] / a.matr[1][1]) * a.matr[1][1];
            }
        }
    }
    return a;
}