想請教小編 為何自訂函數後編譯完還是有問題

{各式移動平均算法}

//函數腳本

//EMA/Xaverage

SetBarMode(2);

input:thePrice(numericseries);

input:Length (Numeric);

variable: Factor(0);

XAverage (20,20);

if length + 1 = 0 then Factor = 1 else Factor = 2 / (Length + 1);

if CurrentBar = 1 then

 XAverage = thePrice;

else

 XAverage = XAverage[1] + Factor * (thePrice - XAverage[1]);