code: public static void Swap(ComplexNumber[][] z) {
          for (int i = 0; i < z.length; i++) {
              for (int j = 0; j < z[0].length; j++) {
                  z[i][j] = new ComplexNumber(z[i][j].imaginary, z[i][j].real);
              }
          }
      }
docs: Swap values between real and imaginary.
  
  @param z Complex number.