> 
> **Possible Duplicate:**  
> 
> [C++: What is the size of an object of an empty class?](https://stackoverflow.com/questions/621616/c-what-is-the-size-of-an-object-of-an-empty-class) 
> 
> 
> 

I have a class without data as the following

```
class A {};

```

I use it to define an object

```
A a;

```

I think object "a" has an address, right? Does it occupy some memory? If so, how many bytes it occupy?

What happens if object "a" with a type void. Thanks a lot!