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Luis
226
Luis 2014.12.17 20:32 

Dear users:


Im trying to code an indicator that shows the MA and EMA of the Volume bars. I have managed to successfully code the SMA but with the EMA, Im getting some issues and I cannot advance. I have detected some stacks overflow also. Anyway below is my code and I dont think I have it good at all. Any more experience can help?


[code]

double EMA_Volume(int i, int size)
   {
      if (i==MA_Period+2)return MA_Volume(i,size);
      
      double multiplier=(2 / (size + 1) ) ;
      return (Volume[i] - EMA_Volume(i+1,10) * multiplier + EMA_Volume(i+1,10));
      
   }

double MA_Volume(int i, int size)
   {
      double suma=0;
      for(int j=i; j<i+size;j++)
         {
            suma=suma+Volume[j];
         }
      if ((suma/size)==0){Alert("Something is wrong with the volume of bar nº= ",i," ",GetLastError());return 50;}
      else
      return (NormalizeDouble((Volume[i]/NormalizeDouble(suma/size,2))*100,2));
   }

[/code]

Carl Schreiber
5960
Carl Schreiber 2014.12.17 20:39  
There is a source button SRC beside the camera!
Carl Schreiber
5960
Carl Schreiber 2014.12.17 20:46  

return() needs its own brackets this won't work

return(Volume[i] - EMA_Volume(i+1,10) * multiplier + EMA_Volume(i+1,10));

better (I am used to this version):

return(  multiplier*(Volume[i] - EMA_Volume(i+1,10)) + EMA_Volume(i+1,10) );

Stack-Overflow or Array out of range?

I would do (using tick_volume[] which should be the prev Volume[]!): (not tested)

 ...
   int i;
   if ( prev_calculated < 100 ) {
      i= rates_total-1;
      emaBuff[i] = (double)tick_volume[i]; // initialize
   } else 
      i = rates_total - prev_calculated + 1;
   while(i>0){i--;
      emaBuff[i] = multipl*((double)tick_volume[i] - emaBuff[i] ) + emaBuff[i];
      ...     

An ema can be easily calculated in a function:

//use: emaVol = ema(multipl, Volume[i], emaVol);
double ema(double c, double newVal, double prvVal){ 
    if ( prvEma == EMPTY_VALUE ) return(newVal); // ini prvVal with EMPTY_VALUE !!
    return( c*(newVal - prvVal) + prvVal); 
} 
Keith Watford
Moderator
7990
Keith Watford 2014.12.17 21:19  

Can a function call itself?

double EMA_Volume(int i, int size)
   {
      if (i==MA_Period+2)return MA_Volume(i,size);
      
      double multiplier=(2 / (size + 1) ) ;
      return (Volume[i] - EMA_Volume(i+1,10) * multiplier + EMA_Volume(i+1,10));
      
   }
/
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