Thread: is this a valid declaration?

Hi,

Please let me know how this a valid definition

Code:

typedef struct
{
	int n[];
}franco;
franco see;
 and 
printf ("sizeof:%d",sizeof(see));

gives Result : 4

and this is not

Code:

main()
{
  int a[];
}

How is the memory allocated when franco is instantiated.
Thanks to all