Operator overloading is a concept to implement the same functionality for user define object (class instance)

Operator overloading permits user-defined operator implementations to be specified for operations where one or both of the operands are of a user-defined class or struct type.

Example

using System;

public struct Complex
{
   public int real;
   public int imaginary;

   public Complex(int real, int imaginary)
   {
      this.real = real;
      this.imaginary = imaginary;
   }

   // Declare which operator to overload (+), the types
   // that can be added (two Complex objects), and the
   // return type (Complex):
   public static Complex operator +(Complex c1, Complex c2)
   {
      return new Complex(c1.real + c2.real, c1.imaginary + c2.imaginary);
   }
   // Override the ToString method to display an complex number in the suitable format:
   public override string ToString()
   {
      return(String.Format("{0} + {1}i", real, imaginary));
   }

   public static void Main()
   {
      Complex num1 = new Complex(2,3);
      Complex num2 = new Complex(3,4);

      // Add two Complex objects (num1 and num2) through the
      // overloaded plus operator:
      Complex sum = num1 + num2;

     // Print the numbers and the sum using the overriden ToString method:
      Console.WriteLine("First complex number:  {0}",num1);
      Console.WriteLine("Second complex number: {0}",num2);
      Console.WriteLine("The sum of the two numbers: {0}",sum);

   }
}

OUTPUT

First complex number:  2 + 3i
Second complex number: 3 + 4i
The sum of the two numbers: 5 + 7i

operator overloading is a concept of extending functionality of exixting operator.for instance take '+' operator.with this operator u can add two integers or u can concatenate two strings.these r the two built in functionalities of '+' operator.other than this two if u want to provide some more functionality to '+' u can achieve with operator overloading.

This is called polymorphism in OOP's . we have constructor overloading,Function overloading, and Opertator overloading.

The Operator overloading is we use '+' sign for Adding two numbers.The same '+'operator can be used to concatenate the strings.

Exam:

int a,b,c;string s1="Hello";

string s2="World";

String con;

c=a+b;

con=s1+s2;

here is + sign is used for addition and concatenation.

simple concept of polymorphism is same person acting differently in different places.