What is operator?

Operators are the symbols, which are used to perform an operation between the operands. As,
a + b
Operands : a and b
Operator : +
Type of operators:
Operators are of two types, which are:
Unary Operators : ++, --, -
Binary Operators : +, -, *, /, >, <, =, == etc.
Why operator overloading is required?
Usually, the operators work with the pre-defind type like int, float, string etc. If you want to perform an operation on the user defined type (object), it is required to re-define the operators (overload) to perform the operation.
  1. Number n1=new Number(10,20);
  2. Number n2=new Number(5,10);
  3. Number n3=n1+n2;
n1 and n2 are two user defined types (object) and + operator is required to perform an addition between the two objects. This is only possible with the operator overloading.
Example:
Create a class to define a user defined type (object).
  1. class Numbers
  2. {
  3. public int num1, num2;
  4. public Numbers()
  5. {
  6. num1 = 0;
  7. num2 = 0;
  8. }
  9. public Numbers(int a,int b)
  10. {
  11. num1 = a;
  12. num2 = b;
  13. }
  14. public void PrintNumbers()
  15. {
  16. Console.WriteLine("Num1 :"+num1);
  17. Console.WriteLine("Num2 :" + num2);
  18. }
  19. }
Write the code to redefine the operators (overload) to perform a user defined operation.
Operator overloading : +
  1. public static Numbers operator +(Numbers ob1, Numbers ob2)
  2. {
  3. Numbers ob3 = new Numbers();
  4. ob3.num1 = ob1.num1 + ob2.num1;
  5. ob3.num2 = ob1.num2 + ob2.num2;
  6. return ob3;
  7. }
Operator overloading : ++
  1. public static Numbers operator ++(Numbers ob1)
  2. {
  3. Numbers ob2 = new Numbers ();
  4. ob2.num1 = ob1.num1 + 1;
  5. ob2.num2 = ob1.num2 + 1;
  6. return ob2;
  7. }
Operator overloading : >
  1. public static bool operator >(Numbers ob1, Numbers ob2)
  2. {
  3. if (ob1.num1 > ob2.num1 && ob1.num2 > ob2.num2)
  4. {
  5. return true;
  6. }
  7. else
  8. {
  9. return false;
  10. }
  11. }
Operator overloading : <
  1. public static bool operator <(Numbers ob1, Numbers ob2)
  2. {
  3. if (ob1.num1 < ob2.num1 && ob1.num2 < ob2.num2)
  4. {
  5. return true;
  6. }
  7. else
  8. {
  9. return false;
  10. }
  11. }
Write the statement in Main method to test the Application.
Statement 1 - To test + operator overloading.
  1. Numbers n1 = new Numbers();
  2. Numbers n2 = new Numbers(10,20);
  3. Numbers n3 = new Numbers(20,30);
  4. n1 = n2 + n3;
  5. n1.PrintNumbers();
Statement 2 - To test ++ operator overloading.
  1. Numbers n1 = new Numbers();
  2. Numbers n2 = new Numbers(10,20);
  3. //Pre increment
  4. n1 = ++n2;
  5. n1.PrintNumbers();
  6. n2.PrintNumbers();
  8. //Post increment
  9. n1 = n2++;
  10. n1.PrintNumbers();
  11. n2.PrintNumbers();
Statement 3 - To test >operator overloading.
  1. Numbers n1 = new Numbers(10,20);
  2. Numbers n2 = new Numbers(20,30);
  3. if (n1 > n2)
  4. {
  5. Console.WriteLine("True");
  6. }
  7. else
  8. {
  9. Console.WriteLine("False");
  10. }
Statement 4 - To test < operator overloading.
  1. Numbers n1 = new Numbers(10,20);
  2. Numbers n2 = new Numbers(20,30);
  3. if (n1 < n2)
  4. {
  5. Console.WriteLine("True");
  6. }
  7. else
  8. {
  9. Console.WriteLine("False");
  10. }
Note

Some of the operators are not overloaded. As- =, ?:,->, sizeof, new etc.The comparison operators must be overloaded in the pairs.
That's all. Thank you. If any suggestion or clarification is required, kindly revert back with the comments.