Coding math Clarification Please.

[Beha Kadıoğlu]

Hi All,

I'm still learning MQL4, I understand much so far, I like to read any MQL4 file I find, and try to understand it, one thing an the following file I give up in it. In the Operator 'for' the author's add number (+9 )? what is the purpose to add this number?

#property indicator_chart_window
#property indicator_buffers 2
#property indicator_color1 Blue
#property indicator_color2 Orange

double CrossUp[];
double CrossDown[];
extern int FasterEMA = 9;
extern int SlowerEMA = 21;
//+------------------------------------------------------------------+
//| Custom indicator initialization function |
//+------------------------------------------------------------------+

int init()
{
//---- indicators

SetIndexStyle(0, DRAW_ARROW, EMPTY);
SetIndexArrow(0, 233);
SetIndexBuffer(0, CrossUp);
SetIndexStyle(1, DRAW_ARROW, EMPTY);
SetIndexArrow(1, 234);
SetIndexBuffer(1, CrossDown);
//----
return(0);
}
//+------------------------------------------------------------------+
//| Custom indicator deinitialization function |
//+------------------------------------------------------------------+
int deinit()
{
//----

//----
return(0);
}
//+------------------------------------------------------------------+
//| Custom indicator iteration function |
//+------------------------------------------------------------------+
int start() {
int limit, i, counter;

double fasterEMAnow, slowerEMAnow, fasterEMAprevious, slowerEMAprevious, fasterEMAafter, slowerEMAafter;

double Range, AvgRange;

int counted_bars=IndicatorCounted();

//---- check for possible errors

if(counted_bars<0) return(-1);

//---- last counted bar will be recounted

if(counted_bars>0) counted_bars--;

limit=Bars-counted_bars;

for(i = 0; i <= limit; i++)
{
counter=i;
Range=0;
AvgRange=0;
for (counter=i ;counter<=i+9;counter++)
{
AvgRange=AvgRange+MathAbs(High[counter]-Low[counter]);
}
Range=AvgRange/10;

fasterEMAnow = iMA(NULL, 0, FasterEMA, 0, MODE_EMA, PRICE_CLOSE, i);
fasterEMAprevious = iMA(NULL, 0, FasterEMA, 0, MODE_EMA, PRICE_CLOSE, i+1);
fasterEMAafter = iMA(NULL, 0, FasterEMA, 0, MODE_EMA, PRICE_CLOSE, i-1);

slowerEMAnow = iMA(NULL, 0, SlowerEMA, 0, MODE_EMA, PRICE_CLOSE, i);
slowerEMAprevious = iMA(NULL, 0, SlowerEMA, 0, MODE_EMA, PRICE_CLOSE, i+1);
slowerEMAafter = iMA(NULL, 0, SlowerEMA, 0, MODE_EMA, PRICE_CLOSE, i-1);

if ((fasterEMAnow > slowerEMAnow) && (fasterEMAprevious < slowerEMAprevious) && (fasterEMAafter > slowerEMAafter)) {
CrossUp[i] = Low[i] - Range*0.3;
}
else if ((fasterEMAnow < slowerEMAnow) && (fasterEMAprevious > slowerEMAprevious) && (fasterEMAafter < slowerEMAafter)) {
CrossDown[i] = High[i] + Range*0.3;
}
}
return(0);
}

Any one can Clarify this for me please?

Regards

[Ray]

He is doing a loop within a loop.

The second loop "for (counter=i ;counter<=i+9;counter++)" goes back 9 bars from the bar position of the first loop "for(i = 0; i <= limit; i++) ".

[okwh]

for (counter=i ;counter<=i+9;counter++)
{
AvgRange=AvgRange+MathAbs(High[counter]-Low[counter]);
}
Range=AvgRange/10;

used for calculate the average of (high -low) from ith to (i+9)th price, total 10 bars.

[Beha Kadıoğlu]

Hi phy and Dxdcn,

Thank you for your replys.

Regards