// my_complex.cc  a partial, non template, complex class
//                demonstrate some operator+ must be non-member functions
//                operator<<  and operator >> must be non-member functions

#include <iostream>
using namespace std;

class my_complex
{
  public:
  my_complex() { re=0.0; im=0.0; }  // three typical constructors
    my_complex(double x) { re=x; im=0.0; }
    my_complex(double x, double y):re(x),im(y) {} // { re=x; im=y; }
    my_complex operator+(my_complex & z) // for  c = a + b
      { return my_complex(re+z.real(), im+z.imag()); }
    my_complex operator+(double x)       // for  c = a + 3.0
      { return my_complex(re+x, im); }
                        // many other operators would typically be defined
    double real(void) { return re; }
    double imag(void) { return im; } 
    friend ostream &operator<< (ostream &stream, my_complex &z);
  private:
    double re; // the data values for this class
    double im;
};

// non member functions
my_complex operator+(double x, my_complex z) // for c = 3.0 + a
{
  return z+x;
}

ostream &operator<< (ostream &stream, my_complex &z)
{
  stream << "(" << z.real() << "," << z.imag() << ")";
  return stream;
}

int main()
{
  my_complex a(2.0, 3.0);              cout << a << " =a\n";
  my_complex b(4.0);                   cout << b << " =b\n";
  my_complex c = my_complex(5.0, 6.0); cout << c << " =c\n";
  my_complex d;                        cout << d << " =d\n";

  c = a + c;                           cout << c << " c=a+c\n";

  c = 3.0 + a; // not legal without non member function operator+
                                       cout << c << " c=3.0+a\n";
  c = a + 3.0; // not legal without second operator+ on double
                                       cout << c << " c=a+3.0\n";
  c = a + 3;   // not legal without second operator+ on double
               // uses standard "C" C++ conversion int -> float -> double
                                       cout << c << " c=a+3\n";
  d = c.imag();                        cout << d << " d=c.imag()\n";
  return 0;
}
// Output from running my_complex.cc
// (2,3) =a
// (4,0) =b
// (5,6) =c
// (0,0) =d
// (7,9) c=a+c
// (5,3) c=3.0+a
// (5,3) c=a+3.0
// (5,3) c=a+3
// (3,0) d=c.imag()