I have a simple question, when I'm writing the .h file of a class and want to pass an argument of type of a different class how should it be written?

For example:

```
#include "y.h"
class x
{
public :
void method( y &)
};

```

In `void method`, is that right? Or should it be written as `y::y&`?
And when it's implemented in a .cpp file?