怎么不赋值定义一个全局变量

技术006

ma2:ma(c,100);
ret1:ret(ma2,100);
ret2:ret(ma2,200);
c1:(ma2/ret1-1)*100;
c2:(pow(ma2/ret2,2)-1)*100;
if  VALID(c1)=1 and VALID(c2)=1 then BEGIN
        if c1>c2 then ma1:=ma2; else ma1:=ma2+0.5;

end

aa:ma1;