rem: Node *node3(a,b,c,d) Node *b, *c, *d;
add: node3(int a, Node *b, Node *c, Node *d)
context: Node *node3(a,b,c,d) Node *b, *c, *d;{	register Node *x;	x = nodealloc(3);	x->nobj = a;	x->narg[0] = b;	x->narg[1] = c;	x->narg[2] = d;	return(x);}