This gives you segmentation fault because pointer e is not initialized - it doesn't point to valid memory.
When you initialize pointer with some address say y - and then apply dereference operator, you tell it to retrieve value from the memory address y which you assigned to it. In your case, no address has been assigned to it, so you can't dereference it.
Make it point to a teste object, then you can dereference it.
In the first example you declare a pointer, but that pointer points to nothing. So you get the seg. fault. You should assing a value to that pointer, being an address of an instance of teste, either declared or created in memory using new() or malloc()