Complex Number

class Complex {
  public double re,im;

  Complex(double re, double im) {
    this.re = re;
    this.im = im;
  }

  Complex somma(Complex a, Complex b) {
    return new Complex(a.re + b.re, a.im + b.im);
  }

  Complex prodotto(Complex a, Complex b) {
    return new Complex(a.re * b.re - a.im * b.im, (a.re * b.im + a.im * b.re));
  }

  double abs() {
    return re*re + im*im;
  }
}