Operator overloading

we can overload an operator ‘+’ in a class like String so that we can concatenate two strings by just using +.
Other example classes where arithmetic operators may be overloaded are Complex Number, Fractional Number, Big Integer, etc.

#include

using namespace std;

 

class Complex {

private:

    int real, imag;

public:

    Complex(int r = 0, int i =0)  {real = r;   imag = i;}

     

    // This is automatically called when '+' is used with

    // between two Complex objects

    Complex operator + (Complex const &obj) {

         Complex res;

         res.real = real + obj.real;

         res.imag = imag + obj.imag;

         return res;

    }

    void print() { cout << real << " + i" << imag << endl; }

};

 

int main()

{

    Complex c1(10, 5), c2(2, 4);

    Complex c3 = c1 + c2; // An example call to "operator+"

    c3.print();

}

Can we overload all operators?
Almost all operators can be overloaded except few. Following is the list of operators that cannot be overloaded.

   . (dot) 
   :: 
   ?: 
   sizeof