Stuck again help plz.

#include <stdio.h>
#include "stdlib.h"
typedef struct node {
	char letter ;
	struct node *Next;
}	NODE_TYPE;

//proto's
NODE_TYPE *getNode();
void displayList(NODE_TYPE *);
NODE_TYPE addToList(NODE_TYPE *);
int emptyList(NODE_TYPE *);

int main(int argc, char **argv)
{
	NODE_TYPE *head = NULL ;
	addToList(head);
	displayList(head);
	fflush(stdin);
	getchar();
	return 0;
}
/*
 * This function addes a new node with info to the head
 * of the list and returns the head
 */
 NODE_TYPE * addToList(NODE_TYPE *head) {
	 int inchar;
 	printf("Please enter a string of dna!\n (enter 0 to end string)") ;
	while((inchar=getchar())!= '0') {
	
	 	if (emptyList(head)==1) {
			head = getNode() ;
			head->Next = NULL ;
			head->letter = inchar ;
		 } else {
	 		NODE_TYPE *temp ;
	 		temp = getNode();
	 		temp->Next = head ;
	 		temp->letter = inchar;
	 		head = temp;
		 }
	}
	 return head ;
 }