code: public void div(Complex c) {
          double modulus = c.real * c.real + c.imag * c.imag;
          double newreal = imag * c.imag + real * c.real;
          double newimag = imag * c.real - real * c.imag;
          real = newreal / modulus;
          imag = newimag / modulus;
      }
docs: Div this value by a complex value