C# ?? "null coalescing operator"

The null-coalescing operator ?? returns the value of its left-hand operand if it isn't null; otherwise, it evaluates the right-hand operand and returns its result. The ?? operator doesn't evaluate its right-hand operand if the left-hand operand evaluates to non-null.

string message = "hello world";
string result = message ?? "It was null";
//result == "hello world";

string message = null;
string result = message ?? "It was null";
//result == "It was null";

Thanks to Scott Guthrie