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simple coding question...

  • #1
  • First Post: Feb 9, 2009 3:37pm Feb 9, 2009 3:37pm
Hi, sorry for the stupid question, but pls help me out here:

If you have any indicator that consists of 1 line in the chart window, and you want to add standard deviation bands to that line, like Bollinger bands. How do you do this:
let's say your buffer that plots your original indicator is named abc
so first you declare these:
extern int BandsPeriod=20;
extern int BandsShift=0;
extern double BandsDeviations=2.0;
1) you change
#property indicator_buffers 1 (1 becomes 3)
2)
SetIndexBuffer(0,abc);
SetIndexStyle(0,DRAW_LINE);
and add
SetIndexBuffer(1,UpperBuffer);
SetIndexStyle(1,DRAW_LINE);
SetIndexBuffer(2,LowerBuffer);
SetIndexStyle(2,DRAW_LINE);
SetIndexDrawBegin(0,BandsPeriod+BandsShift);
SetIndexDrawBegin(1,BandsPeriod+BandsShift);
3) you add the rest of the bollinger bands code into the initialization loop
int start()
{
int i,k,counted_bars=IndicatorCounted();
double deviation,sum,oldval,newres;

//----
if(Bars<=BandsPeriod) return(0);
//---- initial zero
if(counted_bars<1)
and so on....
4) but how the heck do you replace the buffer called MovingBuffer in the original bands.mq4 code by your new buffer from your indicator, called "abc"?

What's the best way to go about this?
Should I try to get my indicator code into the bands.mq4 code or the other way around?

I attached a well-known piece of code called bands.mq4 so you can see what I'm working with.

again, sorry for my coding-ignorance

Maybe someone knows of a 'adding stdev bands tutorial' ? That would be what I need right now. Thx
  • #2
  • Edited 6:10pm Feb 9, 2009 5:59pm | Edited 6:10pm
Quoting MisterH
Hi, sorry for the stupid question, but pls help me out here:

If you have any indicator that consists of 1 line in the chart window, and you want to add standard deviation bands to that line, like Bollinger bands. How do you do this:
let's say your buffer that plots your original indicator is named abc
so first you declare these:
extern int BandsPeriod=20;
extern int BandsShift=0;
extern double BandsDeviations=2.0;
1) you change
#property indicator_buffers 1 (1 becomes 3)
2)
SetIndexBuffer(0,abc);
SetIndexStyle(0,DRAW_LINE);
and add
SetIndexBuffer(1,UpperBuffer);
SetIndexStyle(1,DRAW_LINE);
SetIndexBuffer(2,LowerBuffer);
SetIndexStyle(2,DRAW_LINE);
SetIndexDrawBegin(0,BandsPeriod+BandsShift);
SetIndexDrawBegin(1,BandsPeriod+BandsShift);
3)...
use the iBandsOnArray thing:

iBandsOnArray(array[],total,period,deviation,bands_shift,mode,shift)

array is the obviously your original indicator, just put Bars in the total part, period and deviations are obvious, shift will probably be zero, mode is where you pick MODE_UPPER or MODE_LOWER depending on the band, and shift will be either i or 0, your choice.

just do two of them, one for upper band, one for lower band.


update:
Here's an example of the code:

#property indicator_separate_window
#property indicator_buffers 3
#property indicator_color1 Red
#property indicator_color2 White
#property indicator_color3 White

//---- inputs

extern int Stoch_Period = 5;
extern int Bands_Period = 20;
extern int Deviations = 2;

//---- buffers

double StochBuffer[];
double UpperBuffer[];
double LowerBuffer[];


int init()
{
//----------
SetIndexStyle(0,DRAW_LINE);
SetIndexBuffer(0,StochBuffer);
//----------
SetIndexStyle(1,DRAW_LINE);
SetIndexBuffer(1,UpperBuffer);
//----------
SetIndexStyle(2,DRAW_LINE);
SetIndexBuffer(2,LowerBuffer);

IndicatorShortName("Stoch-Bands example("+Stoch_Period+","+Bands_Period+","+Deviations+")");
//----------
return(0);
}



int start()
{
int limit;
int counted_bars=IndicatorCounted();
//----
if(counted_bars>0) counted_bars--;
limit=Bars-counted_bars;
//----
for(int i=0; i<limit; i++)
StochBuffer[i] = iStochastic(NULL,0,Stoch_Period,3,3,MODE_SMA,PRICE_CLOSE,0,i);
//----
for(i=0; i<limit; i++)
UpperBuffer[i] = iBandsOnArray(StochBuffer,Bars,Bands_Period,Deviations,0,MODE_UPPER,i);
//----
for(i=0; i<limit; i++)
LowerBuffer[i] = iBandsOnArray(StochBuffer,Bars,Bands_Period,Deviations,0,MODE_LOWER,i);
//----
return(0);
}
//+------------------------------------------------------------------+
  • #3
  • Edited 6:16pm Feb 9, 2009 6:02pm | Edited 6:16pm
it's very difficult to explain, very easy to show-
like this (bb macd):
PHP Code
//+------------------------------------------------------------------+
//| MACD_StDvL_basic                                        MACD.mq4 |
//|                      Copyright © 2006, MetaQuotes Software Corp. |
//|                                       http://www.metaquotes.net  |  
//+------------------------------------------------------------------+
//2008 fxtsd     
#property copyright "Copyright © 2006, MetaQuotes Software Corp."
#property link      "http://www.metaquotes.net"
 
#property indicator_separate_window
#property indicator_buffers 4
#property indicator_color1 FireBrick
#property indicator_color2 Maroon
#property indicator_color3 YellowGreen
#property indicator_color4 Green
//---- input parameters
extern int MACD_Fast = 8;     
extern int MACD_Slow = 17;    
extern int MACD_SigMA = 9;    
 
extern double Deviation = 1.62;
extern int StDevPeriod=20;
extern int StDevMethod=0;
 
//---- buffers
double ExtMapBuffer1[];
double ExtMapBuffer2[];
double ExtMapBuffer3[];
double ExtMapBuffer4[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {
  SetIndexBuffer(0,ExtMapBuffer1);
  SetIndexBuffer(1,ExtMapBuffer2);
  SetIndexBuffer(2,ExtMapBuffer3);
  SetIndexBuffer(3,ExtMapBuffer4);
 
  SetIndexStyle(0,DRAW_LINE);
  SetIndexStyle(1,DRAW_LINE);
  SetIndexStyle(2,DRAW_LINE);
  SetIndexStyle(3,DRAW_LINE);
 
IndicatorShortName("MACD_StDv ("+MACD_Fast+","+MACD_Slow+","+MACD_SigMA+") ("+DoubleToStr(Deviation,3)+") ");  
 
   SetIndexLabel(0,"StDevUpLv");
   SetIndexLabel(1,"StDevDnLv");
   SetIndexLabel(2,"MACDSig");
   SetIndexLabel(3,"MACD");
   return(0);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int start()
  {
 
   int    i,limit,counted_bars=IndicatorCounted();
   if(counted_bars<0) return(-1);
   if(counted_bars>0) counted_bars--;
   limit=Bars-counted_bars;
 
 
 
 
   for (i=limit; i>=0; i--)
   {
  ExtMapBuffer4[i]  = iMACD(NULL,0,MACD_Fast,MACD_Slow,MACD_SigMA,0,MODE_MAIN,i);
  ExtMapBuffer3[i]  = iMACD(NULL,0,MACD_Fast,MACD_Slow,MACD_SigMA,0,MODE_SIGNAL,i);
   }
 
 
   for (i=limit; i>=0; i--)
   {  
 
  double std = Deviation*iStdDevOnArray(ExtMapBuffer3,0,StDevPeriod,0,StDevMethod,i);                 
 
 
      ExtMapBuffer1[i]=+std;
      ExtMapBuffer2[i]=-std;
 
 
   }  
  return(0);
 }
//+-------------------------------------------------------+
  • #4
  • Edited 6:31pm Feb 9, 2009 6:09pm | Edited 6:31pm
Quoting blacksun1
use the iBandsOnArray thing:

iBandsOnArray(array[],total,period,deviation,bands_shift,mode,shift)

array is the obviously your original indicator, just put Bars in the total part, period and deviations are obvious, shift will probably be zero, mode is where you pick MODE_UPPER or MODE_LOWER depending on the band, and shift will be either i or 0, your choice.

just do two of them, one for upper band, one for lower band.

that's the good way, B, but the only thing - butbandsonarray - "int"
iBandsOnArray(double array[], int total, int period, int deviation,
so if you need double - or stDev or "iCustom" - "Bands" - like HA it goes standard and it's double
  • #5
  • Last Post: Feb 10, 2009 4:48am Feb 10, 2009 4:48am
thanks guys, I'll get to work on this.
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