! Plot a histogram from a stream of nonzero integers.

let
 const mark ~ '+';
	var n : Integer
in
	begin
	getint (var n); geteol ();
	while n \= 0 do
  let
   var i : Integer;
   var gap : Integer
  in
		 begin
		 gap := if n > 0 then 20 else 20 + n;
		 if n < 0 then  n := 0 - n else ;
	 	i := 0;
		 while i < gap do
		 	begin put (' '); i := i + 1 end;
		 i := 0;
		 while i < n do
		 	begin put (mark); i := i + 1 end;
		 puteol ();
	 	getint (var n); geteol ()
   end
	end