//+------------------------------------------------------------------+
//|                                                  SimplePivot.mq4 |
//|                  Copyright © 2006, Derk Wehler, Global One Group |
//|                                        http://www.metaquotes.net |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2006, Derk Wehler, Global One Group"
#property link      "http://www.metaquotes.net"
//---- input parameters
extern int Lots=1;
//+------------------------------------------------------------------+
//| expert initialization function                                   |
//+------------------------------------------------------------------+
int init()
  {
   return(0);
  }
//+------------------------------------------------------------------+
//| expert deinitialization function                                 |
//+------------------------------------------------------------------+
int deinit()
  {
   return(0);
  }
//+------------------------------------------------------------------+
//| expert start function                                            |
//+------------------------------------------------------------------+
int start()
  {
   static int prevTradeOp=-1;
   static int prevBars=-1;
   static int ticketNum=-1;
//----   
   int curBars=Bars;
   if (prevBars==-1)
      prevBars=curBars;
//----
   Print("curBars, prevBars = ", curBars);
   if (curBars==prevBars)
      return(0);
   Print("After checking bars");
   prevBars=curBars;
   // Only buy and tell on the first tick of new candle creation
   double prevHigh=High[1];
   double prevLow=Low[1];
   double curOpen=Open[0];
   double pivot=(prevHigh + prevLow)/2;
   int tradeOp=OP_BUY;
   // Determine whether we are in a buy or sell position for this candle
   if (curOpen < prevHigh && curOpen > pivot)
      tradeOp=OP_SELL;
   // If we were in a buy, and still in a buy for this new candle, do not 
   // close and re-open the trade, giving up the spread again.  Same for sell.
   if (tradeOp==prevTradeOp && prevTradeOp!=-1)
      return(0);
//----
   Print("Closing old trade");
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
   // Close the current trade
   if (ticketNum!=-1)
     {
      OrderSelect(ticketNum, SELECT_BY_TICKET);
      // long position is opened
      if (OrderType()==OP_BUY)
        {
         OrderClose(ticketNum, OrderLots(), Bid, 0, Violet);
        }
      // short position is opened
      else
        {
         OrderClose(ticketNum, OrderLots(), Ask, 0, Violet);
        }
     }
   Print("Opening new trade");
   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
   // Open new trade
   if (tradeOp==OP_BUY)
     {
      ticketNum=OrderSend(Symbol(), OP_BUY, Lots, Ask, 0, 0,
          0, "Simple Pivot", 55255, 0, Green);
      if (ticketNum > 0)
        {
         if (OrderSelect(ticketNum, SELECT_BY_TICKET))
            Print("BUY order opened : ",OrderOpenPrice());
        }
      else
         Print("Error opening BUY order : ", GetLastError());
     }
   else
     {
      ticketNum=OrderSend(Symbol(), OP_SELL, Lots, Bid, 0, 0,
         0, "CSimple Pivot", 55255, 0, Red);
      if (ticketNum > 0)
        {
         if (OrderSelect(ticketNum, SELECT_BY_TICKET))
            Print("SELL order opened : ", OrderOpenPrice());
        }
      else
         Print("Error opening SELL order : ", GetLastError());
     }
//----
   return(0);
  }
//+------------------------------------------------------------------+