MQL5 Script example

mql5_CTrade.PositionClose.cpp

//+------------------------------------------------------------------+
//|                                           CyClosePositionAll.mq5 |
//|                                                           igotit |
//|                                        http://igotit.tistory.com |
//+------------------------------------------------------------------+
#property copyright "igotit"
#property link      "http://igotit.tistory.com"
#property version   "1.00"

#include <Trade\Trade.mqh>

CTrade trade; 

//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+

///// close only one position which lowest ticket number.
void OnStart() // 
  {
      trade.PositionClose(Symbol());
  }
//+------------------------------------------------------------------+

//// close all postion
void OnStart()
  {
    int maxnum_position = PositionsTotal(); 
    for(int i=0; i<maxnum_position; i++ )  
    {
      trade.PositionClose(Symbol());
    }
     
  }

http://igotit.tistory.com/1832