search( key, t )
	typekey key;
	patricia t;

	{
	if ( t==NULL ) notfound( key );
	else {	while ( !IsData(t) )
			t = bit(t->level,key) ? t->right : t->left;
		if ( key == t->k )	found( t );
			else		notfound( key );
	     }
	};