Complex Complex::add(const Complex& b) const { return Complex(getRe()+b.getRe(), getIm()+b.getIm()); }
Complex Complex::diff(const Complex& b) const { return Complex(getRe()-b.getRe(), getIm()-b.getIm()); }
Complex cplx_plus(Complex a, Complex b) { return Complex(a.getRe() + b.getRe(), a.getIm() + b.getIm()); }