Why for loop is creating variable with the same address?

Question

Why with this code:

unsafe
    {
        for (int i = 0; i < 10; i++)
        {
            Double w = new Double();
            Console.WriteLine((IntPtr)(&w));
        }
    }

i'm always getting the same number? How to create new variables in a loop ? With new addresses ?

The reason, why this is a problem for me is that I need to generate a random double number and then I'm using a pointer (which references to that double) in two objects. In one of the object I'm changing this value and I want it to change in that other object too :)

Answer 1

Logically, that's a new variable every time through the loop. But I hope that you would not expect a new variable to actually be allocated off the stack every time! What if the loop runs a million times? The compiler knows that it can re-use the storage, and it does.

If you want ten different addresses, make an array with ten elements, fix it in place, and take the address of each element.

Answer 2

It seems you want to share the reference to the value of the value type. So, it can be done by wrapping the value type into the reference type:

class Ref<T>
{
    public T Value { get; set; }
}

Please also see the related question: C# - Good and flexible way to pass value types by reference?.