overload-op.cpp

// This example illustrates overloading the plus (+) operator.

#include <iostream>
using namespace std;

class complx
{
      double real,
             imag;
public:
      complx( double real = 0., double imag = 0.); // constructor
      complx operator+(const complx&) const;       // operator+()
      void print();
};

// define constructor
complx::complx( double r, double i )
{
      real = r; imag = i;
}

// define overloaded + (plus) operator
complx complx::operator+ (const complx& c) const
{
      complx result;
      cout << "complx::operator+ this=" << this->real << "," << this->imag << endl;
      cout << "complx::operator+ c=" << c.real << "," << c.imag << endl;
      cout << endl;
      result.real = (this->real + c.real);
      result.imag = (this->imag + c.imag);
      return result;
}

// define print method
void complx::print() { std::cout << "(" << real << "," << imag << ")"; }

int main()
{
      complx x(4,4);
      complx y(6,6);
      complx z = x + y; // calls complx::operator+()

      cout << "x="; x.print(); cout << "\n";
      cout << "y="; y.print(); cout << "\n";
      cout << "z="; z.print(); cout << "\n";
}