with ada.text_io; use ada.text_io; 
with ada.integer_text_io; use ada.integer_text_io; 
 
procedure swaptest is
    procedure swap(x, y: in out integer) is 
        t: constant integer := x;
    begin
        x := y;
        y := t;
    end swap;

    a: integer := 1;
    b: integer := 2;

begin

    put_line(a'img & b'img);

    swap(a, b);

    put_line(a'img & b'img);
end swaptest;