Dong chu chuen dong voi toc do khac nhau

[Godbloc]

Day la` mot chuong trinh` nho nhung no' la` tien` de` cua puong thuc' da nhiem sau nay`

uses crt,dos;
type
crtobj=object
private
timef:longint;
public
str:string;
speed:integer;
procedure strmov(x,y:integer);
procedure getstr(s:string;speed:integer);
end;
procedure gtime(var tim:longint);
var h,m,s,hund:word;
begin
gettime(h,m,s,hund);
tim:=h*3600*99+m*60*99+s*99+hund;
end;

procedure getstr(s:string;spd:integer);
begin
gtime(timef);
str:=s;
speed:=spd;
end;

procedure strmov(x,y:integer);
var
s1,s2:string;
timeaf:longint;
begin
gtime(timeaf);
if timeaf-timef>=speed then
begin
s1:=copy(str,1,1);
s2:=copy(str,2,length(str)-1);
{0320-843659}
str:=s2+s1;
gotoxy(x,y);write(str);
timef:=timeaf;
end;
end;
var
a,b,c:strobj;
begin
a.getstr(' Chao ban toi la` tu ',20);

b.getstr(' Rat han hanh duoc lam` quen ', 30);
c.getstr(' Voi cac ban *****',20 );
repeat
a.strmov(30,10);
b.strmov(30,12);
c.strmov(30,14);
until keypressed;
end.