请问这个程序怎么在金字塔实现??　[金字塔]

编程原理：

d = C – REF(C,1)
If d >= 0, then cmo1i = d and cmo2i = 0
If d <   0, then cmo2i = ABS(-d) and cmo1i = 0
SUM1=SUM(COM1,n);
SUM2=SUM(COM2,n));
CMO = [ (sum1 – sum2) / (sum1 + sum2) ] * 100

金字塔里面if then好像不能赋值变量,请问要怎么弄

d: = C-ref(c,1);

If d >= 0 then BEGIN
  com1: = d;
  com2: = 0;
end

If d <   0 then begin
 com2: = ABS(-d);
    com1: = 0;
end

SUM1:=SUM(COM1,n);
SUM2:=SUM(COM2,n);
CMO: = ((sum1-sum2)/(sum1+sum2))*100;

按这么写CMO1永远是0啊