{Volatility Trend Indicator based on Smoothed True Range
and dynamic period of trend calculation. Copyright (c) konkop 2001}
Inputs:
Len(21), {WATR Lenght}
M(3), {WATR Multiplier}
Max_per(50); {Max. Dynamic Period for Trend Calculation}
Vars: TrueHi(H), TrueLo(L), TrueRng(0), WATR(0), Trend(C), Period(0) ;
{Calculate Smoothed TR}
If Close[1] > High Then TrueHi = Close[1] Else TrueHi = High;
{Calculate TrueHigh}
If Close[1] < Low Then TrueLo = Close[1] Else TrueLo = Low;
{Calculate TrueLow}
TrueRng = TrueHi — TrueLo; {Calculate TrueRange}
WATR = WAverage(TrueRng,Len); {Calculate WATR}
{Trend Calculation}
Condition1= C > Trend[1]; {UpTrend}
Condition2= C <= Trend[1]; { DownTrend}
{SetUp Period When New Trend Begin}
If C Cross over Trend[1] or C Cross Below Trend[1] Then Period = 0;
If Period < Max_per Then Begin {Counting UpTrends with dynamic period}
If Condition1 Then Begin
Period = Period +1;
Trend = Highest(C,Period) — M∗WATR;
End ; {Counting DownTrends with dynamic period}
If Condition2 Then Begin
Period = Period + 1;
Trend = Lowest(C,Period) + M∗WATR;
End;
End Else Begin {Counting UpTrends with constant period}
If Condition1 Then Trend = Highest(C,Max_Per)[1] — M∗WATR;
{Counting DownTrends with constant period}
If Condition2 Then Trend = Lowest(C,Max_per)[1] + M∗WATR;
End; {Plotting Indicator}
Plot1(Trend,»Trend»);

//+------------------------------------------------------------------+
//| WATR.mq4
//| Written WizardSerg under article konkop in "Modern trading" #4/2001
//| http://www.wizardserg.inweb.ru
//| wizardserg@gmail.com
//+------------------------------------------------------------------+
#property copyright "Written WizardSerg under article konkop in  #4/2001"
#property link      "http://www.wizardserg.inweb.ru"
 
#property indicator_chart_window
#property indicator_buffers 2
#property indicator_color1 Coral
#property indicator_color2 DodgerBlue
 
//---- input parameters
extern int       WATR_K = 10;
extern double    WATR_M = 4.0;
extern int       ATR = 21;
 
//---- buffers
double ExtMapBufferUp[];
double ExtMapBufferDown[];
 
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
{  
    IndicatorBuffers(2);  
    SetIndexBuffer(0, ExtMapBufferUp); 
    ArraySetAsSeries(ExtMapBufferUp, true);      
    SetIndexStyle(0, DRAW_LINE, STYLE_SOLID, 2);
    SetIndexBuffer(1, ExtMapBufferDown); 
    ArraySetAsSeries(ExtMapBufferDown, true);      
    SetIndexStyle(1, DRAW_LINE, STYLE_SOLID, 2);
    IndicatorShortName("WATR(" + WATR_K + ", " + WATR_M + ")"); 
    return(0); 
}
  
//+------------------------------------------------------------------+
//| Custom indicator deinitialization function                       |
//+------------------------------------------------------------------+
int deinit()
{
   return(0);
}
 
//+------------------------------------------------------------------+
//| Custom indicator function                                        |
//+------------------------------------------------------------------+
bool AntiTrendBar(int i)
{
    bool res = (TrendUp(i) && (Close[i] < Open[i])) ||         
              (!TrendUp(i) && (Close[i] > Open[i]));    
    return(res);
}
 
//+------------------------------------------------------------------+
//| Custom indicator function                                        |
//+------------------------------------------------------------------+
double CalcIndicValue(int i, bool trend)
{
    double res = Close[i];  
    if(trend)
        res -= (WATR_K*Point + WATR_M*iATR(NULL, 0, ATR, i));
    else
        res += (WATR_K*Point + WATR_M*iATR(NULL, 0, ATR, i));        
    return(res);
}
 
//+------------------------------------------------------------------+
//| Custom indicator function                                        |
//+------------------------------------------------------------------+
bool TrendUp(int i)
{
    return((Close[i+1] > ExtMapBufferUp[i+1]) && (ExtMapBufferUp[i+1] != EMPTY_VALUE));
}
     
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int start()
{
    int limit;
    int counted_bars = IndicatorCounted();
    //---- последний посчитанный бар будет пересчитан
    // if(counted_bars > 0) counted_bars--;
    //---- первое значение индикатора == цене-1 point, т.е. считает тренд восходящим
    ExtMapBufferUp[Bars] = Close[Bars] - WATR_K*Point;     
    // limit = (counted_bars > 0) ? (Bars - counted_bars) : (Bars - 1);
    limit = Bars - counted_bars;
    //if(limit == Bars) limit--;
    //---- основной цикл
    for(int i = limit; i >= 0; i--)
    {
        if( AntiTrendBar(i) )
        {
            ExtMapBufferUp[i] = ExtMapBufferUp[i+1];            
            ExtMapBufferDown[i] = ExtMapBufferDown[i+1];            
        }
        else
        {
            if(TrendUp(i))
            {
                ExtMapBufferUp[i] = CalcIndicValue(i, true);
                if(ExtMapBufferUp[i] < ExtMapBufferUp[i+1])
                    ExtMapBufferUp[i] = ExtMapBufferUp[i+1];                                 
                ExtMapBufferDown[i] = EMPTY_VALUE; 
            }
            else
            {
                ExtMapBufferDown[i] = CalcIndicValue(i, false);                        
                if(ExtMapBufferDown[i] > ExtMapBufferDown[i+1])
                    ExtMapBufferDown[i] = ExtMapBufferDown[i+1];                                             
                ExtMapBufferUp[i] = EMPTY_VALUE;
            }
        }
        // пересечения с ценой                 
        if(TrendUp(i) && (Close[i] < ExtMapBufferUp[i]))
        {
            ExtMapBufferDown[i] = CalcIndicValue(i, false);  
            ExtMapBufferUp[i] = EMPTY_VALUE;
        }
        if((!TrendUp(i)) && (Close[i] > ExtMapBufferDown[i]))
        {
            ExtMapBufferUp[i] = CalcIndicValue(i, true);                  
            ExtMapBufferDown[i] = EMPTY_VALUE; 
        }
    }
    return(0);
}
//+------------------------------------------------------------------+