Signal MACD function ExtState(int ind) analysis

[g2space]

the function as below shows

bool CSignalMACD::ExtState(int ind)
  {
//--- operation of this method results in a bit-map of extremums
//--- practically, the bit-map of extremums is an "array" of 4-bit fields
//--- each "element of the array" definitely describes the ratio
//--- of current extremums of the oscillator and the price with previous ones
//--- purpose of bits of an element of the analyzed bit-map
//--- bit 3 - not used (always 0)
//--- bit 2 - is equal to 1 if the current extremum of the oscillator is "more extreme" than the previous one
//---         (a higher peak or a deeper valley), otherwise - 0
//--- bit 1 - not used (always 0)
//--- bit 0 - is equal to 1 if the current extremum of price is "more extreme" than the previous one
//---         (a higher peak or a deeper valley), otherwise - 0
//--- in addition to them, the following is formed:
//--- array of values of extremums of the oscillator,
//--- array of values of price extremums and
//--- array of "distances" between extremums of the oscillator (in bars)
//--- it should be noted that when using the results of the extended check of state,
//--- you should consider, which extremum of the oscillator (peak or valley)
//--- is the "reference point" (i.e. was detected first during the analysis)
//--- if a peak is detected first then even elements of all arrays
//--- will contain information about peaks, and odd elements will contain information about valleys
//--- if a valley is detected first, then respectively in reverse
   int    pos=ind,off,index;
   uint   map;                 // intermediate bit-map for one extremum
//---
   m_extr_map=0;
   for(int i=0;i<10;i++)
     {
      off=StateMain(pos);
      if(off>0)
        {
         //--- minimum of the oscillator is detected
         pos+=off;
         m_extr_pos[i]=pos;
         m_extr_osc[i]=Main(pos);
         if(i>1)
           {
            m_extr_pr[i]=m_low.MinValue(pos-2,5,index);
            //--- form the intermediate bit-map
            map=0;
            if(m_extr_pr[i-2]<m_extr_pr[i])
               map+=1;  // set bit 0
            if(m_extr_osc[i-2]<m_extr_osc[i])
               map+=4;  // set bit 2
            //--- add the result
            m_extr_map+=map<<(4*(i-2));
           }
         else
            m_extr_pr[i]=m_low.MinValue(pos-1,4,index);
        }
      else
        {
         //--- maximum of the oscillator is detected
         pos-=off;
         m_extr_pos[i]=pos;
         m_extr_osc[i]=Main(pos);
         if(i>1)
           {
            m_extr_pr[i]=m_high.MaxValue(pos-2,5,index);
            //--- form the intermediate bit-map
            map=0;
            if(m_extr_pr[i-2]>m_extr_pr[i])
               map+=1;  // set bit 0
            if(m_extr_osc[i-2]>m_extr_osc[i])
               map+=4;  // set bit 2
            //--- add the result
            m_extr_map+=map<<(4*(i-2));
           }
         else
            m_extr_pr[i]=m_high.MaxValue(pos-1,4,index);
        }
     }
//---
   return(true);

  }

i doubt the sentence ： m_extr_pr[i]=m_low.MinValue(pos-2,5,index);  and   m_extr_pr[i]=m_low.MinValue(pos-1,4,index); 

 why do not  use the price that just at  m_extr_pos[i] to fill  m_extr_pr[i] .