The operator overloading feature of C++ is one of the methods of realizing polymorphism. C++ has the ability to provide the operators with a special meaning to an operator is known as operator overloading.

We can overload all the C++ operators except the following:

• Size resolution operator (::)
• Scope of operator (size of)
• Conditional operator (?:)
• Class member access operator (., .*, →*)
• Pointer to member declarator (::*)

Defining Operator Overloading

The general format of operator overloading is as follows:

{
body of operator function;
}
eg : int operator + ();
void operator – ()

The process of operator overloading involves the following steps:

1. Declare a class (that define the data type) whose objects are to be manipulated using operators.
2. Declare the operator function, in the public part of the class. It can be either a normal member function or a friend function.
3. Define the operator function either within the body of a class or outside the body of the class.

Syntax for invoking the overloaded unary operator function is as follows:

Object operator
Operator object

eg : S++;
++S;

Syntax for invoking the overloaded binary operator function is as follows:

eg : S1 + S2  invokes the overloaded member function + of the S1 object’s class by passing S2 as the argument.