Operator overloading in C#

This post demonstrates how to define your own operators by using user-defined classes that can overload operators .

Operator overloading allows user to define own operator implementations to be specified for operations where the operands are of user-defined or struct type, thus changing their meaning when applied.

The following example changes the behaviour of built-in addition operator. Let name this user-defined operator as “Complex Addition”. Consider a complex number, num = 2+3i, where 2 is a real part and 3i is an imaginary part. So the complex addition operator sums the real parts and imaginary parts of two complex numbers.

Code -

// complex.cs
using System;

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

 //parametrized constructor
 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
*/

---

Please share your thoughts on this post in the comments section.

Karthik Byggari

Author & Editor

Computer Science graduate, Techie, Founder of logicallyproven, Love to Share and Read About pprogramming related things.