Question 1.14

I can't seem to define a linked list successfully. I tried

	typedef struct {
		char *item;
		NODEPTR next;
	} *NODEPTR;

but the compiler gave me error messages. Can't a structure in C contain a pointer to itself?

Structures in C can certainly contain pointers to themselves; the discussion and example in section 6.5 of K&R make this clear. The problem with the NODEPTR example is that the typedef has not been defined at the point where the next field is declared. To fix this code, first give the structure a tag (``struct node''). Then, declare the next field as a simple struct node *, or disentangle the typedef declaration from the structure definition, or both. One corrected version would be

	struct node {
		char *item;
		struct node *next;
	};

	typedef struct node *NODEPTR;

and there are at least three other equivalently correct ways of arranging it.

A similar problem, with a similar solution, can arise when attempting to declare a pair of typedef'ed mutually referential structures.