// C++ does not have a ** operator, instead, ^ (bitwise Xor) is used.
  Mx operator^(int n) {
    if (n < 0)
      throw "Negative exponent not implemented";

    Mx d = identity();
    for (Mx sq = *this; n > 0; sq = sq * sq, n /= 2)
      if (n % 2 != 0)
        d = d * sq;
    return d;
  }
};

typedef SqMx<> M3;
typedef complex<double> creal;

int main() {
  double q = sqrt(0.5);
  creal array[3][3] = { { { q,  0 }, { q, 0 }, { 0, 0 } },
                        { { 0, -q }, { 0, q }, { 0, 0 } },
                        { { 0,  0 }, { 0, 0 }, { 0, 1 } } };
  M3 m(array);

  cout << "m ^ 23=" << endl
       << (m ^ 23) << endl;

  return 0;
}