Is this an if else statement [duplicate]

Question

Possible Duplicate:
What do two question marks together mean in C#?

I just came across the code below and not really sure what it means and can't google it because google omits the ??

int? x = 32;
int  y = x ?? 5;

Is the second line some sort of if else statement, what does the ?? mean

Answer 1

It's called the null-coalescing operator.

If the value to the left of the ?? is null, then use the value to the right of the ?? otherwise use the left hand value.

Expanded out:

y = x == null ? 5 : x

or

if(x == null)
     y = 5
else
     y = x

Answer 2

if(x == null)
     y = 5
else
     y = x

Answer 3

The ?? operator is used with a collection of variables and evaluates to the value of the first non-null variable. For example, consider the following code:

int? x = null;
int? y = null;
int? z = null;

y = 12;
int? a = x ?? y ?? z;

The value of a will be 12, because y is the first variable in the statement with a non-null value.