array and file problem

anthony 2012.11.23 15:17

hi all, this is part of my code

int handle1,handle2,write;
string File_Name="mydata.csv";
double Erray[1,0];
Erray[0,0]=pastfractalup;
Erray[1,0]=pastfractaldown;
{
   if (handle1<1)
      {
      handle1=FileOpen(File_Name,FILE_CSV|FILE_WRITE,";");// File opening
      }
   if (fractalup>0) 
      {
      write=FileWriteDouble(handle1,Erray[0,0],DOUBLE_VALUE);
      }
   else if (fractaldown>0) 
      {
      write=FileWriteDouble(handle1,Erray[1,0],DOUBLE_VALUE);
      }
   FileClose(handle1);
}   
{
   if (handle2<1)
      {
      handle2=FileOpen(File_Name,FILE_CSV|FILE_READ,";");// File opening
      }
   FileReadArray(handle2,Erray, 0, 2);
   FileClose(handle2);   
}

question are

1,is there any thing wrong with the code?

2.in the file_read section, what is the value read out, how to use it?

3,i should have 2 data,erray 0,0 and erray 1,0 ,how to show it out by comment?

William Roeder 2012.11.23 16:26 #1

double Erray[2,1];// [1,0];
Erray[0,0]=pastfractalup;
Erray[1,0]=pastfractaldown;

an array[2] has index 0 and 1

anthony 2012.11.24 10:41 #2

i had change it, but now the problem is, it only attempt to read or write the file, why?
and when it write the data in the file become blank.

William Roeder 2012.11.24 16:17 #3

shenlongming:
i had change it, but now the problem is, it only attempt to read or write the file, why?
and when it write the data in the file become blank.

handle1=FileOpen(File_Name,FILE_CSV|FILE_WRITE,";");// File opening
write=FileWriteDouble(handle1,Erray[0,0],DOUBLE_VALUE);
FileReadArray(handle2,Erray, 0, 2);

You are creating a TEXT file (CSV) and you are using a BINARY write/read functions.

Also the third parameter to FileOpen is an int not a string. RTFM

anthony 2012.11.25 04:22 #4

can you guide me further?

how do i change the binary write to something else?i didnt see any tutorial about that,

Thx a lot.

anthony 2012.11.25 06:15 #5

i had successfully writing the data to the file

int handle1;                               // File descriptor
string File_Name="mydata1.csv";                          // File name
string Erray[2,1];                                       // Array 
string read;
Erray[0,0]=fractalup;
Erray[1,0]=fractaldown;
   {
   handle1=FileOpen(File_Name,FILE_CSV|FILE_WRITE,";");  //File opening
   
   if(fractalup>0)
      {
      FileWrite(handle1,Erray[0,0]);      //Writing to the file
         if(write < 0)                          // If failed
            {
            FileClose(handle1);                // File closing
            return;                             // Exit start()      
            }
      }
      
   Alert("The ",File_Name," file updated.");    // Message
   FileClose(handle1);
   }

now my question is, why the data is not stored in the file?
when fractalup>0, it wrote the value of fractalup,
but then when fractalup=0, the data in the file also became 0, i wonder why?i had no other code related to this one, i dont think it will write data to the file, but why it still gone blank?

PROBLEM CODE storing value problem... What is the optimum

phi nuts 2012.11.25 07:37 #6

You posting an incomplete code. What is the value of write ?

FileWrite(handle1,Erray[0,0]);      //Writing to the file
if (write < 0)                         // If failed

The reason why when fractalup = 0 the data is also 0 is because you using the the FILE_WRITE without FILE_READ. That way, the file operation overwrite/delete the previous data. Try to use

handle1=FileOpen(File_Name,FILE_CSV|FILE_WRITE|FILE_READ,";");  //File opening

I wrote this working script below base on your first code using binary file, but I thought WHRoeder's answer is sufficient enough so I didn't post it

#include <stdlib.mqh>

//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
int start()
  {   
  PlaySound ("wait.wav");
  
  int handle1, handle2, write;
  string File_Name = "mydata.bin";
  double Erray1[2,2], Erray2[2,2];
     Alert ("Declaring array ",ErrorDescription(GetLastError()));

  Erray1[0,0] = 1.23456;
     Alert ("Initialising array 0 0 ",ErrorDescription(GetLastError()));
  Erray1[1,0] = 2.34567;
     Alert ("Initialising array 1 0 ",ErrorDescription(GetLastError()));
  Erray1[0,1] = 3.45678;
     Alert ("Initialising array 0 1 ",ErrorDescription(GetLastError()));
  Erray1[1,1] = 4.56789;
     Alert ("Initialising array 1 1 ",ErrorDescription(GetLastError()));
  
  handle1 = FileOpen(File_Name,FILE_BIN|FILE_WRITE);// File opening
     Alert ("Opening handle 1 ",handle1," ",ErrorDescription(GetLastError()));
  write = FileWriteArray(handle1,Erray1, 0, 4);
     Alert ("Write the file ",write," ",ErrorDescription(GetLastError()));
  FileClose(handle1);

  handle2 = FileOpen(File_Name,FILE_BIN|FILE_READ);// File opening
     Alert ("Opening handle 2 ",handle2," ",ErrorDescription(GetLastError()));
  write = FileReadArray(handle2,Erray2, 0, 4);
     Alert ("Read the file ",write," ",ErrorDescription(GetLastError()));
  FileClose(handle2); 
  
  string txt = DoubleToStr(Erray2[0,0], 8)+" | "+DoubleToStr(Erray2 [1,0],8)+" | "+DoubleToStr(Erray2 [0,1],8)+" | "+DoubleToStr(Erray2 [1,1],8);
     Alert ("See comment too ",txt);
  Comment ("\n",txt);

  return (0);
  }

anthony 2012.11.25 08:05 #7

phi.nuts:

You posting an incomplete code. What is the value of write ?

The reason why when fractalup = 0 the data is also 0 is because you using the the FILE_WRITE without FILE_READ. That way, the file operation overwrite/delete the previous data. Try to use

I wrote this working script below base on your first code using binary file, but I thought WHRoeder's answer is sufficient enough so I didn't post it

int handle1,handle2,write;                               // File descriptor
string File_Name="mydata1.csv";                          // File name
string Erray[2,1];                                       // Array 
string read;
Erray[0,0]=fractalup;
Erray[1,0]=fractaldown;
   {
   handle1=FileOpen(File_Name,FILE_CSV|FILE_WRITE,";");  //File opening
   
   if(fractalup>0)
      {
      FileWrite(handle1,Erray[0,0]);      //Writing to the file
         if(write < 0)                          // If failed
            {
            FileClose(handle1);                // File closing
            return;                             // Exit start()      
            }
      }
      
   //else FileClose(handle1);                          // File closing
   Alert("The ",File_Name," file updated.");    // Message
   FileClose(handle1);
   }
//------------------------------------------------------------------------
   {
   handle2=FileOpen(File_Name,FILE_CSV|FILE_READ,";");  //File opening
   read=FileReadString(handle2);
   pastfractalup=StrToDouble(read);
   FileClose(handle2);
   }

sorry i didnt post the file entirely, now the file is nearly posted, the fractalup may =0 or 1.2345

the result is the same after using the file read,anymore suggestion?
if fractalup>0, it wrote the value of fractalup,this is done perfectly
but then when fractalup=0, the data in the file also became 0, should it be kept?
why it still gone blank?

storing value problem... Help! Not sure how Errors, bugs, questions

phi nuts 2012.11.25 08:50 #8

I'm not so sure what you're looking for, so I re-write the code and I hope it fix this time

#include <stdlib.mqh>
//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
int start()
  {   
  PlaySound ("wait.wav");
  
  int handle1, handle2, write;       // File variable
  string File_Name="mydata1.csv";    // File name
  string Erray[2,1];                 // Array ==>> this array Erray [2, 1] is actually the same like Erray [2]
  string read;

  double fractalup = 1.234567890, fractaldown = 2.345678901, pastfractalup;

  Erray[0,0] = fractalup;
  Erray[1,0] = fractaldown;

   {
   if(fractalup > 0)
      {
      if (handle1 == 0)
        {
         handle1 = FileOpen(File_Name,FILE_CSV|FILE_WRITE,";");  //--- File opening
         if (handle1 > 0)
            {
            write = FileWrite(handle1,Erray[0,0]);               //--- Writing to the file
            if (write <= 0)
                Print ("Failed writing to file handle1 ", ErrorDescription (GetLastError()));
                else
                Print ("Success writing to file handle1 with ",write," character written.");
            FileClose (handle1);
            handle1 = 0;
            //return;                                              //--- exit start
            }
            else
            {
            Print ("Failed to open file handle 1 ", ErrorDescription (GetLastError())); 
            }
        }
     }
   }
//------------------------------------------------------------------------
   {
   handle2 = FileOpen(File_Name,FILE_CSV|FILE_READ,";");  //File opening
   read = FileReadString(handle2);
   pastfractalup = StrToDouble(read);
   if (handle2 > 0)
      {
      FileClose(handle2);
      handle2 = 0;
      }
   Print ("Value from handle2 is ",read);
   }

anthony 2012.11.25 11:32 #9

thanks you very much, i see what is my problem already, i should put the condition first before open a file and close it right after, thx a lot phi.nuts

anthony 2012.11.29 13:00 #10

int handle1,handle2,handle3,write;                               // File descriptor
string File_Name="fractalup.csv";                          // File name
string File_Name2="fractaldown.csv"; 
string Erray[2,1];                                       // Array 
string read;
Erray[0,0]=fractalup;
Erray[1,0]=fractaldown;
   
      {
      if(fractalup>0)                                             //store fractal to serve as entry Point
         {
         handle1=FileOpen(File_Name,FILE_CSV|FILE_WRITE,";");     //File opening
         FileWrite(handle1,Erray[0,0]);                           //Writing to the file
            if(write < 0)                                         // If failed
               {
               FileClose(handle1);                                // File closing
               return;                                            // Exit start()      
               }
         FileClose(handle1);
         //Alert("The ",File_Name," file updated.");                // Message
         }
      if (fractaldown>0)
         {
         handle2=FileOpen(File_Name2,FILE_CSV|FILE_WRITE,";");     //File opening
         FileWrite(handle2,Erray[1,0]);                           //Writing to the file
            if(write < 0)                                         // If failed
               {
               FileClose(handle2);                                // File closing
               return;                                            // Exit start()      
               }
         FileClose(handle2);
         //Alert("The ",File_Name," file updated.");                // Message
         }
      }
//------------------------------------------------------------------------
      {
      handle3=FileOpen(File_Name,FILE_CSV|FILE_READ,";");         //File opening
      read=FileReadString(handle3);
      pastfractalup=StrToDouble(read);
      FileClose(handle3);
      }
      {
      handle3=FileOpen(File_Name2,FILE_CSV|FILE_READ,";");         //File opening
      read=FileReadString(handle3);
      pastfractaldown=StrToDouble(read);
      FileClose(handle3);
      }

hi can anyone show me how to simplify the code above?

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