MODULE TreeVisual;

IMPORT In, Line, Oberon;

CONST timeout = 1000;

TYPE Node* = POINTER TO NodeDesc;
					NodeDesc* = RECORD
						key: INTEGER;
						left,right:Node;
					END;
					
			Tree* = POINTER TO TreeDesc;
					TreeDesc = RECORD
						root: Node;
					END;


PROCEDURE show*(T:Tree);		(* Tree grafisch ausgeben *)
	
	CONST breadth=90;
		
	TYPE Point=RECORD;
			x,y: INTEGER;
			END;
	VAR  last, root, act:Point;time:LONGINT;
	
			PROCEDURE Drawline(n:Node; level:INTEGER; from, to: Point);
				BEGIN
					IF n#NIL THEN
							Line.Line (from.x,from.y, to.x,to.y, (level MOD 2)*2+1,1);
							from:=to;to.x:=from.x-(breadth DIV (level));to.y:=from.y-50;
							Drawline(n^.left,level+1,from,to);
							to.x:=from.x+(breadth DIV (level));to.y:=from.y-50;
							Drawline(n^.right,level+1,from,to);
						END;
				END Drawline;
	BEGIN
		IF ~Line.Init(1024,768,10,720,630,40,320,380,1,1) THEN RETURN; END;
		Line.Clear(120, 180, 400, 400);
		root.x:=320; root.y:=550;
		Drawline(T^.root,1, root, root)
END show;

PROCEDURE insert(VAR n:Node; new:Node);
	BEGIN
		IF (n=NIL) THEN
			n:=new;
		ELSIF (n^.key>new^.key) THEN
			insert(n^.left,new);
		ELSE
			insert(n^.right,new);
		END;
	END insert;
	

PROCEDURE test*();
	VAR node:Node;key:INTEGER;t:Tree;time:LONGINT;
	BEGIN
		NEW(t);
		In.Open;
		In.Int(key);
		WHILE (In.Done) DO
			NEW(node);
			node^.key:=key;
			node^.right:=NIL;
			node^.left:=NIL;
			insert(t^.root,node);
			show(t);
			time:=Oberon.Time();
			WHILE (Oberon.Time()<time+timeout) DO END;
			In.Int(key);
		END;
END test;

END TreeVisual.

	
System.Free TreeVisual~
TreeVisual.test 43 7 1 4 98 12 6~