implicit conversion from 'number' to 'string' warning

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Jerry Spence
215
Jerry Spence  

I have:

bool   MyVar = false;

When I try and display a comment:

Comment ("MyVar: " + MyVar);

I get implicit conversion from 'number' to 'string' warning when compiling.

In MT4 it would compile OK and print a 'one' or 'zero' corresponding to true or false. How do we now display booleans in a Comment?

-Jerry

Paul
748
Paul  
netconuk posted  :

I have:

bool   MyVar = false;

When I try and display a comment:

Comment ("MyVar: " + MyVar);

I get implicit conversion from 'number' to 'string' warning when compiling.

In MT4 it would compile OK and print a 'one' or 'zero' corresponding to true or false. How do we now display booleans in a Comment?

-Jerry

This is due to more stringent type-checking in MQL5, which has many benefits of picking up coding errors.

 If you want to eliminate the warnings, you need to explicitly type-cast the variable, as in

Comment ("MyVar: " + (string)MyVar);

Or use the multiple parameter feature of Comment() 

Comment ("MyVar: ",MyVar);

 Or perhaps better still

Comment ("MyVar: ",BoolToString(MyVar));



string BoolToString(bool b)
{
   if (b) return("true");
   else return("false");
}
 

 Paul

http://paulsfxrandomwalk.blogspot.com/ 

Regularly emailing the status of an account
  • 2012.06.14
  • Paul
  • paulsfxrandomwalk.blogspot.com
Prompted by a query, I thought I'd post a useful little utility that I have used for ages which emails the status of the account every hour.  After lengthy deliberation I decided to call it .... EmailStatus.  With only a small modification it could be used to log the status to a file, and the time...
Jerry Spence
215
Jerry Spence  
string BoolToString(bool b)
{
   if (b) return("true");
   else return("false");
}

Thanks Paul. That's a great Help.Actually BoolToString would be a useful command to be included in MT5.

-Jerry

Paul
748
Paul  

 Glad you like BoolToString - attached is a stack of string utilities  :)

 From time to time this will need updating as MetaQuotes adds extra error codes.

Paul

http://paulsfxrandomwalk.blogspot.com/ 

Regularly emailing the status of an account
  • 2012.06.14
  • Paul
  • paulsfxrandomwalk.blogspot.com
Prompted by a query, I thought I'd post a useful little utility that I have used for ages which emails the status of the account every hour.  After lengthy deliberation I decided to call it .... EmailStatus.  With only a small modification it could be used to log the status to a file, and the time...
Files:
pkelatlheletswe
5
pkelatlheletswe  

HELP ME I HAVE THE SAME PROBLEM

//+------------------------------------------------------------------+

//|                                             binaryinvest-lib.mq4 |

//|                        Copyright 2017, MetaQuotes Software Corp. |

//|                                             https://www.mql5.com |

//+------------------------------------------------------------------+

#property library

#property copyright "Copyright 2017, MetaQuotes Software Corp."

#property link      "https://www.mql5.com"

#property version   "1.00"

#property strict

//+------------------------------------------------------------------+

//| My function                                                      |

//+------------------------------------------------------------------+

// int MyCalculator(int value,int value2) export

//   {

//    return(value+value2);

//   }

//+------------------------------------------------------------------+

  #import "shell32.dll"

int ShellExecuteW(

    int hwnd,

    string Operation,

    string File,

    string Parameters,

    string Directory,

    int ShowCmd

);

#import


#import "wininet.dll"

int InternetOpenW(

    string     sAgent,

    int        lAccessType,

    string     sProxyName="",

    string     sProxyBypass="",

    int     lFlags=0

);

int InternetOpenUrlW(

    int     hInternetSession,

    string     sUrl, 

    string     sHeaders="",

    int     lHeadersLength=0,

    uint     lFlags=0,

    int     lContext=0 

);

int InternetReadFile(

    int     hFile,

    uchar  &   sBuffer[],

    int     lNumBytesToRead,

    int&     lNumberOfBytesRead

);

int InternetCloseHandle(

    int     hInet

);       

#import


#define INTERNET_FLAG_RELOAD            0x80000000

#define INTERNET_FLAG_NO_CACHE_WRITE    0x04000000

#define INTERNET_FLAG_PRAGMA_NOCACHE    0x00000100


int hSession_IEType;

int hSession_Direct;

int Internet_Open_Type_Preconfig = 0;

int Internet_Open_Type_Direct = 1;


int hSession(bool Direct)

{

    string InternetAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; Q312461)";

    

    if (Direct) 

    { 

        if (hSession_Direct == 0)

        {

            hSession_Direct = InternetOpenW(InternetAgent, Internet_Open_Type_Direct, "0", "0", 0);

        }

        

        return(hSession_Direct); 

    }

    else 

    {

        if (hSession_IEType == 0)

        {

           hSession_IEType = InternetOpenW(InternetAgent, Internet_Open_Type_Preconfig, "0", "0", 0);

        }

        

        return(hSession_IEType); 

    }

}


string httpGET(string strUrl)

{

   int handler = hSession(false);

   int response = InternetOpenUrlW(handler, strUrl, NULL, 0,

        INTERNET_FLAG_NO_CACHE_WRITE |

        INTERNET_FLAG_PRAGMA_NOCACHE |

        INTERNET_FLAG_RELOAD, 0);

   if (response == 0) 

        return(false);

        

   uchar ch[100]; string toStr=""; int dwBytes, h=-1;

   while(InternetReadFile(response, ch, 100, dwBytes)) 

  {

    if (dwBytes<=0) break; toStr=toStr+CharArrayToString(ch, 0, dwBytes);

  }

  

  InternetCloseHandle(response);

  return toStr;

}


void httpOpen(string strUrl)

{

  Shell32::ShellExecuteW(0, "open", strUrl, "", "", 3);

}

Automated Trading and Strategy Testing
Automated Trading and Strategy Testing
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Choose a suitable trading strategy and subscribe to it with a few clicks. All Signals are provided with detailed statistics and informative charts. Become a trading signal provider and sell subscriptions to thousands of traders around the world. With the Signals service, your successful strategy can generate income with a small start-up budget...
Files:
Sergey Golubev
Moderator
114343
Sergey Golubev  
DipperSoftware
26
DipperSoftware  
  • //+------------------------------------------------------------------+
    //|                                               Indicator: BUY.mq5 |
    //|                                       Created with EABuilder.com |
    //|                                             http://eabuilder.com |
    //+------------------------------------------------------------------+
    #property copyright "Created with EABuilder.com"
    #property link      "http://eabuilder.com"
    #property version   "1.00"
    #property description ""
  • //--- indicator settings
    #property indicator_chart_window
    #property indicator_buffers 2
    #property indicator_plots 2
  • #property indicator_type1 DRAW_ARROW
    #property indicator_width1 1
    #property indicator_color1 0xFFAA00
    #property indicator_label1 "'BUY"
  • #property indicator_type2 DRAW_ARROW
    #property indicator_width2 1
    #property indicator_color2 0x0000FF
    #property indicator_label2 "'BUY"
  • //--- indicator buffers
    double Buffer1[];
    double Buffer2[];
  • datetime time_alert; //used when sending alert
    bool Audible_Alerts = true;
    double myPoint; //initialized in OnInit
    int BearsPower_handle;
    double BearsPower[];
    int BullsPower_handle;
    double BullsPower[];
    int Volumes_handle;
    double Volumes[];
    double Low[];
  • void myAlert(string type, string message)
      {
       if(type == "print")
          Print(message);
       else if(type == "error")
         {
          Print(type+" | BUY @ "+Symbol()+","+Period()+" | "+message);
         }
       else if(type == "order")
         {
         }
       else if(type == "modify")
         {
         }
       else if(type == "indicator")
         {
          Print(type+" | BUY @ "+Symbol()+","+Period()+" | "+message);
          if(Audible_Alerts) Alert(type+" | BUY @ "+Symbol()+","+Period()+" | "+message);
         }
      }
  • //+------------------------------------------------------------------+
    //| Custom indicator initialization function                         |
    //+------------------------------------------------------------------+
    int OnInit()
      {  
       SetIndexBuffer(0, Buffer1);
       PlotIndexSetDouble(0, PLOT_EMPTY_VALUE, 0);
       PlotIndexSetInteger(0, PLOT_ARROW, 241);
       SetIndexBuffer(1, Buffer2);
       PlotIndexSetDouble(1, PLOT_EMPTY_VALUE, 0);
       PlotIndexSetInteger(1, PLOT_ARROW, 241);
       //initialize myPoint
       myPoint = Point();
       if(Digits() == 5 || Digits() == 3)
         {
          myPoint *= 10;
         }
       BearsPower_handle = iBearsPower(NULL, PERIOD_H1, 27);
       if(BearsPower_handle < 0)
         {
          Print("The creation of iBearsPower has failed: BearsPower_handle=", INVALID_HANDLE);
          Print("Runtime error = ", GetLastError());
          return(INIT_FAILED);
         }
      
       BullsPower_handle = iBullsPower(NULL, PERIOD_M20, 27);
       if(BullsPower_handle < 0)
         {
          Print("The creation of iBullsPower has failed: BullsPower_handle=", INVALID_HANDLE);
          Print("Runtime error = ", GetLastError());
          return(INIT_FAILED);
         }
      
       Volumes_handle = iVolumes(NULL, PERIOD_H1, VOLUME_TICK);
       if(Volumes_handle < 0)
         {
          Print("The creation of iVolumes has failed: Volumes_handle=", INVALID_HANDLE);
          Print("Runtime error = ", GetLastError());
          return(INIT_FAILED);
         }
      
       return(INIT_SUCCEEDED);
      }
  • //+------------------------------------------------------------------+
    //| Custom 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 limit = rates_total - prev_calculated;
       //--- counting from 0 to rates_total
       ArraySetAsSeries(Buffer1, true);
       ArraySetAsSeries(Buffer2, true);
       //--- initial zero
       if(prev_calculated < 1)
         {
          ArrayInitialize(Buffer1, 0);
          ArrayInitialize(Buffer2, 0);
         }
       else
          limit++;
       datetime Time[];
      
       if(CopyBuffer(BearsPower_handle, 0, 0, rates_total, BearsPower) <= 0) return(rates_total);
       ArraySetAsSeries(BearsPower, true);
       if(CopyBuffer(BullsPower_handle, 0, 0, rates_total, BullsPower) <= 0) return(rates_total);
       ArraySetAsSeries(BullsPower, true);
       if(CopyBuffer(Volumes_handle, 0, 0, rates_total, Volumes) <= 0) return(rates_total);
       ArraySetAsSeries(Volumes, true);
       if(CopyLow(Symbol(), PERIOD_CURRENT, 0, rates_total, Low) <= 0) return(rates_total);
       ArraySetAsSeries(Low, true);
       if(CopyTime(Symbol(), Period(), 0, rates_total, Time) <= 0) return(rates_total);
       ArraySetAsSeries(Time, true);
       //--- main loop
       for(int i = limit-1; i >= 0; i--)
         {
          if (i >= MathMin(5000-1, rates_total-1-50)) continue; //omit some old rates to prevent "Array out of range" or slow calculation  
          //Indicator Buffer 1
          if(BearsPower[i] < 0 //Bears Power < fixed value
          && BullsPower[i] > BullsPower[1+i] //Bulls Power > Bulls Power
          && BullsPower[i] > 0 //Bulls Power > fixed value
          && BullsPower[1+i] > 0 //Bulls Power > fixed value
          && Volumes[i] > Volumes[1+i] //Volumes > Volumes
          )
            {
             Buffer1[i] = Low[i]; //Set indicator value at Candlestick Low
             if(i == 0) myAlert("indicator", "'BUY"); //Instant alert, unlimited
            }
          else
            {
             Buffer1[i] = 0;
            }
          //Indicator Buffer 2
          if(BearsPower[i] > 0 //Bears Power > fixed value
          && BullsPower[i] > BullsPower[1+i] //Bulls Power > Bulls Power
          && BullsPower[i] > 0 //Bulls Power > fixed value
          && BullsPower[1+i] > 0 //Bulls Power > fixed value
          && BullsPower[2+i] > BullsPower[1+i] //Bulls Power > Bulls Power
          && Volumes[i] > Volumes[1+i] //Volumes > Volumes
          )
            {
             Buffer2[i] = Low[i]; //Set indicator value at Candlestick Low
             if(i == 0) myAlert("indicator", "'BUY"); //Instant alert, unlimited
            }
          else
            {
             Buffer2[i] = 0;
            }
         }
       return(rates_total);
      }
    //+------------------------------------------------------------------+
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Konstantin Nikitin
7908
Konstantin Nikitin  
DipperSoftware:

Enter the code correctly

Oluwaseyi Olakojo
159
Oluwaseyi Olakojo  

Good morning house. please kindly help me, I have an indicator that displayed 33 warnings after compiling it, but I don`t have idea of what to change . I want to ask for permission before pasting it.

Thanks

Seng Joo Thio
1216
Seng Joo Thio  
pkelatlheletswe:

HELP ME I HAVE THE SAME PROBLEM

You just have to figure out WHAT you want your function to return - a string? or bool?

string httpGET(string strUrl)
{
   int handler = hSession(false);
   int response = InternetOpenUrlW(handler, strUrl, NULL, 0,
        INTERNET_FLAG_NO_CACHE_WRITE |
        INTERNET_FLAG_PRAGMA_NOCACHE |
        INTERNET_FLAG_RELOAD, 0);
   if (response == 0) 
        return(false);
   uchar ch[100]; string toStr=""; int dwBytes, h=-1;
   while(InternetReadFile(response, ch, 100, dwBytes)) 
  {
    if (dwBytes<=0) break; toStr=toStr+CharArrayToString(ch, 0, dwBytes);
  }
  InternetCloseHandle(response);
  return toStr;
}
Seng Joo Thio
1216
Seng Joo Thio  
DipperSoftware:

Just have to add the highlighted parts:

void myAlert(string type, string message)
  {
   if(type == "print")
      Print(message);
   else if(type == "error")
     {
      Print(type+" | BUY @ "+Symbol()+","+EnumToString(Period())+" | "+message);
     }
   else if(type == "order")
     {
     }
   else if(type == "modify")
     {
     }
   else if(type == "indicator")
     {
      Print(type+" | BUY @ "+Symbol()+","+EnumToString(Period())+" | "+message);
      if(Audible_Alerts) Alert(type+" | BUY @ "+Symbol()+","+EnumToString(Period())+" | "+message);
     }
  }
12
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