Faktorial

program faktorial;
uses wincrt;
procedure faktorial(var n : integer; var hasil : integer);
var i : integer;
begin
hasil := 1;
for i := n downto 1 do
hasil := hasil * i;
end;

var
bil,hsl : integer;
begin
write('Input Bilangan : ');readln(bil);
faktorial(bil,hsl);
writeln(bil,'! = ',hsl);
readln;
end.