C# FAQ: Are references the same in Cplusplus and CSharp

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Are references the same in C++ and C#?

There is one significant difference between C++ and C# references: C# references can be null. Therefore, a C# reference may not point to a valid object. A C# reference is a bit like a C++ pointer in this regard.

An attempt to reference a null reference will cause a NullReferenceException to be thrown. For example, a method such as the following:

void displayStringLength (string displayString)
{
   Console.WriteLine ("String length is: {0}.", 
      displayString.Length);
}

The preceding method will throw a NullReferenceException if called with a null reference as follows:

displayStringLength (null);

In many situations, a NullReferenceException may be a valid result. However, it would be better to rewrite the preceding example to catch null references like this:

void displayStringLength (string displayString)
{
   if( displayString == null )
   {
      Console.WriteLine ("String reference is null.");
   }
   else
   {
      Console.WriteLine ("String length is: {0}.", 
         displayString.Length);
   }
}