Learn New MQL Coding

Quoting broketrader

Disliked

Hi Gumrai and Kiads, It's nice that at least two people are interested in this thing . I still will wait to see if there are a couple more and then slowly start. To start with something simple, I propose to write a simple Moving Average indicator with bits from existing code but writing it from scratch and then moving to it's Object Oriented version.

Ignored

 
//+------------------------------------------------------------------+
//|                                              MyMovingAverage.mq4 |
//|                                                      Broketrader |
//|                                              http://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright                 "Broketrader"
#property link                      "http://www.mql5.com"
#property version                   "1.00"
#property strict
#property indicator_chart_window    
#property indicator_buffers         1
#property indicator_plots           1
#property indicator_label1          "Main"
#property indicator_type1           DRAW_LINE
#property indicator_color1          clrRed
#property indicator_style1          STYLE_SOLID
#property indicator_width1          1
 
 
/********************************************************************
   Global Variables
********************************************************************/
double                              MainBuffer[];
 
 
/********************************************************************
   OnInit()
   Initializes Indicator globaal Variables
********************************************************************/
int OnInit() {
   SetIndexBuffer(0,MainBuffer);
  
   return(INIT_SUCCEEDED);
}
 
 
/********************************************************************
   OnCalculate()
   Indicator Iteration function
********************************************************************/
int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[])
{
   return(rates_total);
}
 
 
/********************************************************************
   End of File
********************************************************************/

if( a <  10 ) {
  b++;
}

if( a < 10 )
{
   b++;
}

if( a < 10 ) {
  b++;
}

if( a < 19 )
  b++;

if( a < 10 ) { b++; }

  
if( a < 10 ) 
   {
   b++;
   }

Quote

Disliked

Global Practices :

Avoid putting multiple classes in a single file.

Quoting Gumrai

Disliked

... but I have no idea what classes are. I don't think that they existed before the upgrade. If you could explain in "dummy" language, I will be grateful.

Ignored

input int                           MAPeriod = 14;
input int                           MAShift  = 0;
input ENUM_MA_METHOD                MAMethod = MODE_SMA;
input ENUM_APPLIED_PRICE            MAPrice  = PRICE_CLOSE;

/********************************************************************
   OnInit()
   Initializes Indicator globaal Variables
********************************************************************/
int OnInit() {
   IndicatorBuffers( 1 );                    // We have only one indicator
   IndicatorDigits( Digits );                // Digits showwhen visualizing indicator value.
   SetIndexStyle( 0, DRAW_LINE );            // MA shown as a simple line
   SetIndexBuffer( 0, MainBuffer );          // Associate buffer to index.
   SetIndexShift( 0, MAShift );              // Apply user shift
   SetIndexLabel( 0, "MyMovingAverage" );    // Index Label
   ArrayInitialize( MainBuffer ,0);          // Initializes the array
  
   // Check that input parameter is valid
   if( MAPeriod <= 0 ) {
      Print( "Wrong input parameter MAPeriod" );
      return INIT_FAILED;
   }
  
   return INIT_SUCCEEDED;
}

/********************************************************************
   OnCalculate()
   Indicator Iteration function
********************************************************************/
int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[])
{
   int i, Start;
  
   // If there are not enough rates,
   // i.e less than desired period, we just return.
   if( rates_total <= MAPeriod ) {
      return 0;
   }
  
   // We don't use data as series
   ArraySetAsSeries( MainBuffer, false );
   ArraySetAsSeries( close, false );
  
   if( prev_calculated == 0 ) {
      // Calculates first visible value.
      double FirstValue=0;
      Start = MAPeriod;
      for( i=0; i<Start; i++ ){
         FirstValue += close[i];
      }
      FirstValue /= MAPeriod;
      MainBuffer[Start-1] = FirstValue;
   }
   else {
      Start = prev_calculated - 1;
   }
   for( i=Start; i<rates_total && !IsStopped(); i++ ) {
      MainBuffer[i] = MainBuffer[i-1] + (close[i]-close[i-MAPeriod]) / MAPeriod;
   }
   // Return number of calculated rates.
   return(rates_total);
}

Quoting broketrader

Disliked

Here is the code :

Ignored

{
    static int Start = 0;
    // If there are enough rates
    if( rates_total > MAPeriod ) {
        if(Start > 0) {
            for( int i = Start; i < rates_total && !IsStopped(); i++ ) {
                MainBuffer[i] = MainBuffer[i - 1] + (close[i] - close[i - MAPeriod]) / MAPeriod;
            }
            Start = rates_total - 1;
            return(rates_total);
        }
        else {
            // Calculates first visible value.
            double FirstValue = 0;
            Start = MAPeriod;
            for( int i = 0; i < Start; i++ ) {
                FirstValue += close[i];
            }
            MainBuffer[Start - 1] = FirstValue / MAPeriod;
            // rest of it
            for( int i = Start; i < rates_total && !IsStopped(); i++ ) {
                MainBuffer[i] = MainBuffer[i - 1] + (close[i] - close[i - MAPeriod]) / MAPeriod;
            }
            Start = rates_total - 1;
        }
    }
    return(rates_total);
}

Quoting rockit

Disliked

{quote} Would like to throw in a small optimisation advice: In branch prediction, forward conditional jumps are by default not taken, while backward conditional jumps are by default taken (like in loops). Therefore, do not code: if(less likely condition) else (more likely condition), but if(more likely condition) [...] return; else (less likely condition) So, your OnCalculate() would look something like this: { static int Start = 0; // If there are enough rates if( rates_total > MAPeriod ) { if(Start > 0) { for( int i = Start; i < rates_total &&...

Ignored

Quoting AimHigher

Disliked

are you saying that it makes a difference in terms of execution speed

Ignored