Expert Advisor Programming by Andrew R. Young

Order Placement
bottom of the file) and assign the return values to our global variables. We'll use these when
referencing point or slippage values in the rest of our expert advisor.
Next is the start() function, our main program execution. We've left out deinit(), since we have
no use for it here. The iMA() function calculates the moving average The FastMA variable holds our
10 period moving average, which is set using the FastMAPeriod variable. The SlowMA variable is our
20 period moving average, set using SlowMAPeriod. Everything else is set to default (a no shift,
simple moving average calculated on the close price).
We use the if operator to define our order opening conditions. If the current 10 period moving
average (the FastMA) is greater than the 20 period moving average (the SlowMA), and if BuyTicket
is equal to 0, we will open a buy order.
Before we open the buy order, we will close the current sell order, if it exists. We use OrderSelect()
to retrieve the current SellTicket. If the order close time is 0 (indicating that the order has not yet
been closed), and the SellTicket is greater than 0 (indicating that the SellTicket is likely valid),
we will go ahead and close the sell order. We retrieve the lot size of the sell order and the current
Ask price, which will be the closing price for the sell order. Then, we close the sell order using
OrderClose().
Next, we assign the current Ask price to the OpenPrice variable – this will be the opening price of
our buy order. We calculate our stop loss and take profit relative to the opening price, checking first
to make sure that we have specified a StopLoss or TakeProfit value in the settings. Then, we place
the order using the OrderSend() function, and store the order ticket in BuyTicket. Lastly, we clear
the value of SellTicket, allowing the placement of another sell order when the order condition
becomes valid.
The sell order block follows the same logic as the buy order block. We close the buy order first, and
use the Bid as the OpenPrice and the buy order ClosePrice. The stop loss and take profit
calculations are reversed.
The start() function ends with a return operator. Our custom PipPoint() and GetSlippage()
functions are defined at the end after the start() function. We will include these functions in every
example in this book.
Using Pending Orders
Let's modify our EA to use pending orders. We'll use stop orders in this example. When the fast
moving average is greater than the slow moving average, we will place a buy stop order 10 pips
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