C# Operators

Let's look at operators in C#, shall we? 😁

is operator

This operator evaluates the type of a variable (type compatibilty):

var color = "purple";

if (color is string)

increment and decrement

These operators are ++ and -- which add and respectively substract 1 from a number.

The interesting thing here is that we can put these operators before or after the variable.

var number = 1;
Console.WriteLine(number);   // 1
Console.WriteLine(number++); // 1
Console.WriteLine(++number); // 3


Whenever you want to use a variable during a statement and then increment, put the ++ operator after.

If you want to first increment and then use the variable during that statement, put the ++ operator before.


  • number++ – use, then increment
  • ++number – increment, then use

&& and ||

One interesting thing about the && operator is short-circuiting.

If we have any object, we can use the && operator to type safe code:

  • in the first part we check if it's diffferent than null
  • if it is, we can call properties and method on it
List<int> numbers = null;

if (numbers != null && numbers.Contains(0))

But if we replace && with ||, it throws a NullReferenceException exception.

Why? 😱

Because of short-circuiting: whenever we use the && operator and the first part is false, then the compiler doesn't even bother continuing. C# offers also these operators: & and |, but they don't short-circuit.