Example: gcd
function gcd(a,b: integer): integer;
(* Compute gcd of a, b  *)
var   temp: integer;
begin
   while b <> 0 do
     begin
       temp := a mod b;
       a := b;
       b := temp
     end;
   gcd := a
end;
temp = a % b;
a = b;
b = temp;