Expert Advisor Programming by Andrew R. Young

EXPERT ADVISOR PROGRAMMING
}
if(BuyStopLoss > 0 || BuyTakeProfit > 0)
{
bool TicketMod = OrderModify(BuyTicket,OrderOpenPrice(),BuyStopLoss,
BuyTakeProfit,0);
}
The OrderSend() function is identical to our earlier example, except that we use a value of 0 for the
stop loss and take profit parameters. A value of zero means that there is no stop loss or take profit
being placed with the order. The BuyTicket variable stores the ticket number of the order.
We use an if statement to check that the BuyTicket number is valid – i.e. greater than zero. If so,
we call the OrderSelect() function using our BuyTicket number. We retrieve the opening price for
the order using OrderOpenPrice(), and assign that to the OpenPrice variable.
Next, we calculate the stop loss and take profit, relative to the opening price of the order we just
placed. We check first to see if the StopLoss and TakeProfit external variables are greater than
zero. If so, we calculate the new stop loss and/or take profit price.
Finally, we call the OrderModify() function to add our stop loss and take profit to the order. We
check first to make sure that the BuyStopLoss or BuyTakeProfit variables are something other than
zero. If we attempt to modify the order with unchanged values, we'll get an error code 1 from the
OrderModify() function.
The first parameter for OrderModify() is our BuyTicket number. We could also use OrderTicket()
as well. The second parameter is the new order price. Since we are not modifying the order price, we
use the OrderOpenPrice() function, to indicate that the order price is unchanged.
Remember that we can only modify order prices for pending orders. If we are modifying a market
order, we can pass any value for the Price parameter, since you cannot change the order price of a
market order. But we cannot assume that we will always be modifying market orders, so we will
always use OrderOpenPrice().
The BuyStopLoss and BuyTakeProfit variables pass the changed stop loss and take profit values to
the OrderModify() function. If you plan on using order expiration times for your pending orders,
you can use OrderExpiration() as the unchanged Expiration parameter. Otherwise, just use 0.
Although this method adds a few extra steps, we recommended that you use this method of placing
stop losses and take profits for market orders in your expert advisors to ensure that they are
compatible with all brokers. This method also has the advantage of allowing us to place accurate stop
loss and take profit prices without the effects of slippage.
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