program scroll_text;

uses crt;

const
   SPC = ' ';

var
   text      : string;
   x,y,len,i : byte;
   start,fin : byte;

begin
   textmode(80);
   randomize;
   textcolor(black);
   clrscr;

   textcolor(10);
   write('Please type in a sentence : ');
   textcolor(11);
   read(text);
   textcolor(black);
   clrscr;

   if text = '' then
      text := 'This is a small pascal program called Scroll_Text'; {49 chars}

   len := length(text);
   start := 1; fin := 1;
   x := 80; y := 13;

   repeat
{     gotoxy(x,y);
      write(SPC:len);}

      textcolor(9);
      gotoxy(x,y);
      for i := start to fin do
         write(text[i]);

      textcolor(black);
      gotoxy(1,25);

      delay(14); { try 7 }
      dec(x,1);

      if x > 1 then
      begin
         inc(fin,1);
         if fin = len then
            fin := len;
      end else
      if x < 1 then
      begin
         inc(start,1);
         x := 1;
      end;

      if start = len+2 then
      begin
         start := 1; fin := 1;
         x := 80;
         y := random(24)+1;
      end;
   until keypressed;
   textcolor(lightgray);
   clrscr;
end.