编写要求：
MACD在零下13日内2次金叉的选股公式。
www.gszx.com.cn网解答：
DIFF:=EMA(CLOSE,12) - EMA(CLOSE,26),COLORWHITE,LINETHICK1;
DEA:=EMA(DIFF,9),COLORYELLOW,LINETHICK2;
JCCOUNT:=COUNT(CROSS(DIFF,DEA),BARSLAST(DEA>=0));
二次金叉:CROSS(DIFF,DEA) AND DEA<0 AND COUNT(JCCOUNT=2,13)=1;
