(G) would be legal.
What you are doing is dereferenceing a pointer to a structure, and assigning that contained value to the left hand variable.
Consider the following:
struct mystruct x,y,*z;
z = &y; /* ok, z == y now */
x = y; /* perfectly valid */
Thus:
x = *z; /* also perfectly valid */
Recall that by dereferencing a pointer, you are saying "give me the value stored at this location".
(n) is not legal.
You cannot just initialize a structure instance all in one shot like that. Consider the following:
struct mystruct { int x; char y[1024]; float z; };
Given an instance of 'mystruct', called 'abc', you cannot just:
abc = 1;
Which is what you would in effect be doing by assigning it NULL.
However, you can do:
int x = NULL;
That is legal.
Quzah.
