20均線模型請教

ma20:=stkindi('sh000300','ma.ma3',0,datatype);

if cross(c,ma20)  then begin

sellshort(holding<0,0,market);

buy(holding=0,1,market);

end

if cross(ma20,c) then begin

sell(holding>0,0,market);

buyshort(holding=0,1,market);

end