#include <stdio.h>
#include <stdlib.h>

#define dumpptr(P) printf("%u\n", (unsigned int) (P));

typedef struct TreeNode {
	int label;
	struct TreeNode* next;
} TreeNode;


TreeNode* treenode_new(int l, TreeNode* v) {
	TreeNode* t;
	t = malloc(sizeof(TreeNode));
	t->label = l;
	t->next = v;
	return t;
}

void treenode_find_blank(TreeNode** t, TreeNode** dest) {

	*dest = *t;
	
	while (*dest) {
	
		dumpptr(*t);
		dumpptr(*dest);
		dumpptr(&(*dest)->next);
		printf("--\n");
	
		*dest = ((*dest)->next);
	}
	
		dumpptr(*t);
		dumpptr(dest);
		printf("--\n");

	
}

int main (void) {

	TreeNode* a;
    TreeNode* dest;

	a = treenode_new(0, NULL);
	a->label = 10;
	treenode_find_blank(&a, &dest);
	
	dumpptr(dest);
	
	return 0;
}