MQL5 : Risk percentage based lotsize XAUUSD

 double calculate_lot(double ep, double sl,double contractSize)

  {

   double accountBal=AccountInfoDouble(ACCOUNT_BALANCE);

   double riskval= accountBal* riskpercentage* 0.01;

   Print("account bal: "+accountBal);

   Print("riskval: "+riskval);

   double diff_ep_sl=MathAbs(ep-sl);

   Print("diff_ep_sl: "+diff_ep_sl);

   diff_ep_sl=diff_ep_sl*contractSize;

   Print("diff_ep_sl * 100: "+diff_ep_sl);

   lots=riskval/diff_ep_sl;

   lots= NormalizeDouble(lots, 2);

   Print("lots : "+lots);

   return lots;

  }