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ExpertMoney.mqh

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och
486
och  

Hi All,

 I tried to understand ExpertMoney.mqh. Is there someone who can explain this part of that class?

Even if we are using a derivated class and if we are surcharging CheckopenLong and checkOpenClose, according to me the end of thoses functions should be :

....  

if(lot<m_symbol.LotsMin()) return(m_symbol.LotMin());

   if(lot>m_symbol.LotsMax()) return(m_symbol.LotMax());    

//---

   return(lot);

  

 ----------- extract from standard library

//+------------------------------------------------------------------+

//| Getting lot size for open long position.                         |

//| INPUT:  no.                                                      |

//| OUTPUT: lot-if successful, 0.0 otherwise.                        |

//| REMARK: no.                                                      |

//+------------------------------------------------------------------+

double CExpertMoney::CheckOpenLong(double price,double sl)

  {

   if(m_symbol==NULL) return(0.0);

//---

   double lot;

   if(price==0.0)

      lot=m_account.MaxLotCheck(m_symbol.Name(),ORDER_TYPE_BUY,m_symbol.Ask(),m_percent);

   else

      lot=m_account.MaxLotCheck(m_symbol.Name(),ORDER_TYPE_BUY,price,m_percent);

   if(lot<m_symbol.LotsMin()) return(0.0);

//---

   return(m_symbol.LotsMin());

  } 

Documentation on MQL5: Standard Constants, Enumerations and Structures / Trade Constants / Order Properties
  • www.mql5.com
Standard Constants, Enumerations and Structures / Trade Constants / Order Properties - Documentation on MQL5
hornsALERT
62
hornsALERT  
You are right. It should be
if(lot<m_symbol.LotsMin()) return(0.0);


Nguyen Nhu Phan
18
Nguyen Nhu Phan  

@hornsALERT is right. It should return 0.0 when lot<LostMin() for the limits of desired Margin

The code from standard library that quoted by @och  just return 0.0 or m_symbol.LotsMin(), return 0.0 when lot<m_symbol.LotsMin() is OK, otherway why not return lot instead of m_symbol.LotsMin()Does anyone explain?

lot=m_account.MaxLotCheck(...);

The function m_account.MaxLotCheck(...);  in AccountInfo.mqh alredy check for minvol and maxvol (see code below). I think, it is not necessary to recheck like the code above.

//+------------------------------------------------------------------+
//| Access functions OrderCalcMargin(...).                           |
//| INPUT:  name            - symbol name,                           |
//|         trade_operation - trade operation,                       |
//|         price           - price of the opening position,         |
//|         percent         - percent of available margin [1-100%].   |
//+------------------------------------------------------------------+
double CAccountInfo::MaxLotCheck(const string symbol,const ENUM_ORDER_TYPE trade_operation,
                                 const double price,const double percent) const
  {
   double margin=0.0;
//--- checks
   if(symbol=="" || price<=0.0 || percent<1 || percent>100)
     {
      Print("CAccountInfo::MaxLotCheck invalid parameters");
      return(0.0);
     }
//--- calculate margin requirements for 1 lot
   if(!OrderCalcMargin(trade_operation,symbol,1.0,price,margin) || margin<0.0)
     {
      Print("CAccountInfo::MaxLotCheck margin calculation failed");
      return(0.0);
     }
//---
   if(margin==0.0) // for pending orders
      return(SymbolInfoDouble(symbol,SYMBOL_VOLUME_MAX));
//--- calculate maximum volume
   double volume=NormalizeDouble(FreeMargin()*percent/100.0/margin,2);
//--- normalize and check limits
   double stepvol=SymbolInfoDouble(symbol,SYMBOL_VOLUME_STEP);
   if(stepvol>0.0)
      volume=stepvol*MathFloor(volume/stepvol);
//---
   double minvol=SymbolInfoDouble(symbol,SYMBOL_VOLUME_MIN);
   if(volume<minvol)
      volume=0.0;
//---
   double maxvol=SymbolInfoDouble(symbol,SYMBOL_VOLUME_MAX);
   if(volume>maxvol)
      volume=maxvol;
//--- return volume
   return(volume);
  }
//+------------------------------------------------------------------+
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