Help me to correct this function

double CalcVolumeByStopLoss(double price, double sl, double risk)
{
   double delta=MathAbs(price-sl);
   int contract=SymbolInfoDouble(Symbol(),SYMBOL_TRADE_CONTRACT_SIZE);
   delta=delta*contract;
   bool convert=false;
   if(SymbolInfoInteger(Symbol(),SYMBOL_TRADE_CALC_MODE)==SYMBOL_CALC_MODE_FOREX)convert=true;
   string accntcurr=AccountInfoString(ACCOUNT_CURRENCY);
   string tradecurr=StringSubstr(Symbol(),3,3);
   MqlRates Rates[];
   if(convert && tradecurr!=accntcurr)
   {
      if(CopyRates(accntcurr+tradecurr,0,0,1,Rates)>0)
      {
         delta=delta*Rates[0].close;
      }
      else
      {
         if(CopyRates(tradecurr+accntcurr,0,0,1,Rates)>0)
         {
            if(Rates[0].close>0)
            {
               delta=delta/Rates[0].close;
            }
         }
      }
   }  
   double budget=AccountInfoDouble(ACCOUNT_MARGIN_FREE);
   budget=budget*risk/100;
   double lot=NormalizeDouble(budget/delta,2); //*SymbolInfoDouble(Symbol(),SYMBOL_TRADE_TICK_SIZE);
   if(lot<0.01)lot=0.01;
   if(lot>SymbolInfoDouble(Symbol(),SYMBOL_VOLUME_MAX))lot=SymbolInfoDouble(Symbol(),SYMBOL_VOLUME_MAX);
   if(lot<SymbolInfoDouble(Symbol(),SYMBOL_VOLUME_MIN))lot=SymbolInfoDouble(Symbol(),SYMBOL_VOLUME_MIN);
   Alert("Lot="+lot);
   return(lot);
}