What is operator overloading in C++?

In this C++ interview questions, we will learn about:

• what is operator overloading in c++?

• properties of operator overloading in c++
• example of operator overloading in c++

---

What is Operator Overloading in C++?

Operator overloading is a type of polymorphism that gives C++ ability to the operator with preference to data type and have user-defined meaning to it.

 

Example: using '+' operator, two strings can be concatenated.

 

Properties of Operator Overloading

• The overloaded operator has a return type and parameter list.
• Operations happened over user-defined data types.
• In this feature, C++ allows programmers to redefine the meaning of operator.

Syntax of operator overloading in c++

 

Return_type class :: operator

sign_of_operator(argument1, argument2,...)
{
//function definition
}

Operator Overloading can be done by implementing on this type of functions:

• member/non-member functions and
• friend function.

Example of operator overloading in c++

Operator overloading in c++ example is given below:

/* Program of operator overloading for Unary Minus operator */
#include <iostream> 
#include<conio.h>
using namespace std;  

class Un 
 {  
    unsigned int c;

   public:  
        Un()    
        {    
            c=0;    
        }    
        Un(int c1)   
        {    
            c=c1;    
        }  
        int counter()
        {
            return c;
        }
        void operator -()
        {
            c=-c;
        }
}; 
 
int main()   
{  
    Un c2(50),c3(100);
    cout<<"C1:"<<c2.counter()<<endl;
    cout<<"C2:"<<c3.counter()<<endl;
    -c3;
    cout<<"C1:"<<c2.counter()<<endl;
    cout<<"C2:"<<c3.counter()<<endl;
    return 0;  
}  

OUTPUT

C1:50

C2:100

C1:50

C2:-100

 

The operators that are not overloaded:

• sizeof
• scope resolution operator(::)
• ternary operator(?:)