// Complex Class as given in Ch. 4 of A Tour of C++, Bjarne Stroustrup, (both 2014 & 2018)

// partial implementation, with differences from Stroustrup's version

class complex {
   double re, im;
public:
   complex(double r = 0, double i = 0) : re{r}, im{i} { }
   
   double real() const { return re; }
   double imag() const { return im; }
   
   complex& operator=(complex other) {
      re = other.re;
      im = other.im;
      return *this;
   }

   complex& operator+=(complex other) {
      re += other.re;
      im += other.im;
      return *this;
   }
};

complex operator+(complex a, complex b) {
   complex result;
   result = a;
   result += b;
   return result;
}

// DANGEROUS definition of ==
bool operator==(complex a, complex b) {
   return a.real() == b.real() && a.imag() == b.imag();
}