Управление точкой на экране — Pascal(Паскаль)

uses graph, crt;

var
  gd, gm, x, y, x1, y1: integer;
  c: char;

label 0, 1, 2, 3, 4;

begin
  initgraph(gd, gm, 'c:\bp\bgi');
  y := 50;
  x := 50;
  outtext('Press up, down, left ,right aroow keys for moving the point');
  outtextxy(10, 10, 'Press Esc to Exit');
0:
  c := readkey;
  if c = chr(27) then
    halt;
  if ord(c) = 72 then
    goto 1;
  if ord(c) = 80 then
    goto 2;
  if ord(c) = 75 then
    goto 3;
  if ord(c) = 77 then
    goto 4;
  GOTO 0;
1:
  y := y - 1;
  IF y < 1 THEN
    y := 2;
  putpixel(x1, y1, 0);
  putpixel(x, y, 15);
  x1 := x;
  y1 := y;
  goto 0;
2:
  putpixel(x, y, 0);
  y := y + 1;
  IF y > 479 THEN
    y := 478;
  putpixel(x1, y1, 0);
  putpixel(x, y, 15);
  x1 := x;
  y1 := y;
  goto 0;
3:
  x := x - 1;
  IF x < 1 THEN
    x := 2;
  putpixel(x1, y1, 0);
  putpixel(x, y, 15);
  x1 := x;
  y1 := y;
  goto 0;
4:
  x := x + 1;
  IF x > 639 THEN
    x := 638;
  putpixel(x1, y1, 0);
  putpixel(x, y, 15);
  x1 := x;
  y1 := y;
  goto 0;

end.