我觉得第3楼的编太烦啦,我的是:
var
    a,b,t,gcd,lcm:integer;
  begin
    readln(a,b);
    lcm:=a*b;
    if a<b
      then
        begin
          t:=a;
          a:=b;
          b:=t;
        end;
    if (a mod b=0)
        then gcd:=b
        else
          begin
            while (a mod b<>0) do
              begin
                t:=b;
                b:=a mod b;
                a:=t;
              end;
            gcd:=b;
          end;
    lcm:=lcm div gcd;
    writeln('gcd:',gcd,'  lcm:',lcm);{gcd是最大公约数,lcm是最小公倍数}
  end.
**我是初学,若不对请多指教!!!!