sample2.pas

var x, y, z, q, r, n, f;

procedure multiply;
var a, b;
begin
  a := x;
  b := y;
  z := 0;
  while b > 0 do
  begin
    if odd b then z := z + a;
    a := 2 * a;
    b := b / 2
  end
end;

procedure divide;
var w;
begin
  r := x;
  q := 0;
  w := y;
  while w <= r do
    w := 2 * w;
  while w > y do
  begin
    q := 2 * q;
    w := w / 2;
    if w <= r then
    begin
      r := r - w;
      q := q + 1
    end
  end
end;

procedure gcd;
var f, g;
begin
  f := x;
  g := y;
  while f # g do
  begin
    if f < g then g := g - f;
    if g < f then f := f - g
  end;
  z := f
end;

procedure fact;
begin
  if n > 1 then
  begin
    f := n * f;
    n := n - 1;
    call fact
  end
end;


begin
  x := 3;
  y := 6;
  call multiply;

  x := 3;
  y := 6;
  call divide;

  x := 3;
  y := 6;
  call gcd;

  f := 1;
  n := 10;
  call fact
end.