The program I wrote: (Although the result is not good, the program is correct)

////is followed by a text description, which you don't need to write when writing the model.

MA8:=MA(CLOSE，8)； //Simple moving average of closing price of 8 cycles

MA2 1:=MA (closing, 21); //2 1 Simple moving average of periodic closing price

Cross (MA8, MA2 1), bk; //When MA8 passes MA2 1, send a buy and open order.

CROSS(MA2 1，MA8)，SK； //When MA2 1 and MA8 are threaded, issue a sell and open the transaction instruction.

(CLOSE-MA2 1)> 100，BP； //

(ma 2 1- off) > 100, sp; //