How to use Operator Overloading in C#?

Overloaded operators are functions with special name. The keyword operator is followed by the symbol for the operator being defined. Similar to any other function, an overloaded operator has a return type and a parameter list.

The following table shows which operators can be overloaded and which cannot −

The overloaded operator is defined as −

public static Box operator+ (Box b, Box c) { }

Example

The following is an example showing how to work with Operator Overloading in C# −

 Live Demo

using System;

namespace OperatorOvlApplication {
   class Box {
      private double length; // Length of a box
      private double breadth; // Breadth of a box
      private double height; // Height of a box

      public double getVolume() {
         return length * breadth * height;
      }

      public void setLength( double len ) {
         length = len;
      }

      public void setBreadth( double bre ) {
         breadth = bre;
      }

      public void setHeight( double hei ) {
         height = hei;
      }

      // Overload + operator to add two Box objects.
      public static Box operator+ (Box b, Box c) {
         Box box = new Box();
         box.length = b.length + c.length;
         box.breadth = b.breadth + c.breadth;
         box.height = b.height + c.height;
         return box;
      }
   }

   class Tester {
      static void Main(string[] args) {
         Box Box1 = new Box(); // Declare Box1 of type Box
         Box Box2 = new Box(); // Declare Box2 of type Box
         Box Box3 = new Box(); // Declare Box3 of type Box
         double volume = 0.0; // Store the volume of a box here

         // box 1 specification
         Box1.setLength(6.0);
         Box1.setBreadth(7.0);
         Box1.setHeight(5.0);

         // box 2 specification
         Box2.setLength(12.0);
         Box2.setBreadth(13.0);
         Box2.setHeight(10.0);

         // volume of box 1
         volume = Box1.getVolume();
         Console.WriteLine("Volume of Box1 : {0}", volume);

         // volume of box 2
         volume = Box2.getVolume();
         Console.WriteLine("Volume of Box2 : {0}", volume);

         // Add two object as follows:
         Box3 = Box1 + Box2;

         // volume of box 3
         volume = Box3.getVolume();
         Console.WriteLine("Volume of Box3 : {0}", volume);
         Console.ReadKey();
      }
   }
}

Output

Volume of Box1 : 210
Volume of Box2 : 1560
Volume of Box3 : 5400