EA draw trendline from i highest to specific price but 10 candle advance

Hefajatur Rahman  
      double popen = iOpen(Symbol(),0,1);
  double PHighest = High[iHighest(Symbol(),0,MODE_HIGH,10,0)];
double PLowest  =  Low[iLowest(Symbol(),0,MODE_LOW,10,0)];

Where the fault error: Time[PHighest] need integer value, Time[-10] is it not possible, if i draw horizontal line in popen, can i get the point of Hline nad Tline cross point?