Overloading Binary Operator

Overloading Binary Operator

Why do we need Operator overloading in C++?

Operators in C++ like +, -, *, / can operate in datatypes like int, float, double etc as predefined operational meanings. But these operators can’t operate in user-defined datatypes like objects without extension or adding some sort of code to alter their operational meaning.
Such a way of extending the operational functionality of certain operators in C++ is called operator overloading.

Which operators can we overload and which we cannot?

Following are the operators that cannot be overloaded

• pointer to member access operator ( .* )
• scope resolution operator ( :: )
• member access operator ( . )
• condition operator ( ?: )
• size operator ( sizeof )
• run-time type information operator ( typeid )

Following is the list of overloadable operators

Category	Operators
Airthmetic	+ , – , * , / , %
Bit-wise	& , | , ~ , ^ , << , >>
Bit-wise assignment	&= , |= , ^= , <<== , >>=
Relational	< , > , == , != , <= , >=
Logical	|| , && , !
Assignment	=
Arithmetic assignment	-=, += , *= , /= , %=
Unary	++ , —
Subscripting	[ ]
Deference	*
Function call	( )
Address of	&
Member access through member pointer	->*
Member access through object pointer	->
Dynamic Allocation and release	new, delete, new[ ], delete[ ]
Comma	,

Write a C++ program to overload binary operator '+' to add two complex numbers.

#include<iostream>
using namespace std;

class Complex
{
        int num1, num2;
    public:
        void accept()
        {
                cout<<"\n Enter Two Complex Numbers : ";
                cin>>num1>>num2;
        }
        Complex operator+(Complex obj)   //Overloading '+' operator
        {
                Complex c;
                c.num1=num1+obj.num1;
                c.num2=num2+obj.num2;
                return(c);
        }
        void display()
        {
                cout<<num1<<"+"<<num2<<"i"<<"\n";
        }
};
int main()
{
        Complex c1, c2, sum;      //Created Object of Class Complex i.e c1 and c2 

        c1.accept();  //Accepting the values
        c2.accept();

        sum = c1+c2;   //Addition of object
    
        cout<<"\n Entered Values : \n";
        cout<<"\t";
        c1.display();    //Displaying user input values
        cout<<"\t";
        c2.display();
  
        cout<<"\n Addition of Real and Imaginary Numbers : \n";
        cout<<"\t";
        sum.display();  //Displaying the addition of real and imaginary numbers
     
        return 0;
}

Output: