******** fig3.14 **********

	/* Uses a header.  If element is not found, then next field */
	/* of returned value is NULL */

	position
	find_previous( element_type x, LIST L )
	{
		position p;

/*1*/		p = L;
/*2*/		while( (p->next != NULL) && (p->next->element != x) )
/*3*/			p = p->next;

/*4*/		return p;
	}