Viết chường trình tính n!(n giai thừa).giúp e vs mn

$\text{program giai_thua;}$
$\text{uses crt;}$
$\text{var i, n, t : longint ;}$
$\text{begin }$
$\text{clrscr;}$
$\text{write('nhap so n : ');readln(n);}$
$\text{t := 1;}$
$\text{for i:= 1 to n  do }$
$\text{t:= t*i;}$
$\text{writeln('gia tri cua t la:', t );}$
$\text{readln}$
$\text{end.}$

program ct;

uses crt;

var i,n:integer;

      gt:longint;

begin clrscr;

   write('Nhap so n: '); readln(n);

     gt:=1;

   for i:=1 to n do

     gt:=gt*i;

   writeln(n,' giai thua la: ',gt);

readln;

end.