Initialize to None

[N.S. via Digitalmars-d-learn]

I'd like to check whether a variable is initialized or not. And 
I'd also like to uninitialize a variable that is already 
initialized. Thanks!

int x = void;
if (x == void)
{
    writeln("x not initialized");
}
else
{
    // OK, use x
}

// Uninitialize x
x = void;