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FileReadFloat

Reads the single-precision floating point number (float) from the current position of the binary file.

float  FileReadFloat(
   int  file_handle    // File handle
   );

Parameters

file_handle

[in]  File descriptor returned by FileOpen().

Return Value

The value of float type.

Note

For more details about the error, call GetLastError().

Example (the file obtained after executing the example for FileWriteFloat function is used here)

//+------------------------------------------------------------------+
//|                                           Demo_FileReadFloat.mq5 |
//|                        Copyright 2013, MetaQuotes Software Corp. |
//|                                              https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2013, MetaQuotes Software Corp."
#property link      "https://www.mql5.com"
#property version   "1.00"
#property indicator_separate_window
#property indicator_buffers 2
#property indicator_plots   1
//---- plot Label1
#property indicator_label1  "CloseLine"
#property indicator_type1   DRAW_COLOR_LINE
#property indicator_color1  clrRed,clrBlue
#property indicator_style1  STYLE_SOLID
#property indicator_width1  2
//--- parameters for data reading
input string InpFileName="Close.bin"// file name
input string InpDirectoryName="Data"// directory name
//--- global variables
int      ind=0;
int      size=0;
double   close_buff[];
datetime time_buff[];
//--- indicator buffers
double   buff[];
double   color_buff[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
   int def_size=100;
//--- allocate memory for the arrays
   ArrayResize(close_buff,def_size);
   ArrayResize(time_buff,def_size);
//--- open the file
   ResetLastError();
   int file_handle=FileOpen(InpDirectoryName+"//"+InpFileName,FILE_READ|FILE_BIN);
   if(file_handle!=INVALID_HANDLE)
     {
      PrintFormat("%s file is available for reading",InpFileName);
      PrintFormat("File path: %s\\Files\\",TerminalInfoString(TERMINAL_DATA_PATH));
      //--- read data from the file
      while(!FileIsEnding(file_handle))
        {
         //--- read time and price values
         time_buff[size]=(datetime)FileReadDouble(file_handle);
         close_buff[size]=(double)FileReadFloat(file_handle);
         size++;
         //--- increase the array sizes if they are overflown
         if(size==def_size)
           {
            def_size+=100;
            ArrayResize(close_buff,def_size);
            ArrayResize(time_buff,def_size);
           }
        }
      //--- close the file
      FileClose(file_handle);
      PrintFormat("Data is read, %s file is closed",InpFileName);
     }
   else
     {
      PrintFormat("Failed to open %s file, Error code = %d",InpFileName,GetLastError());
      return(INIT_FAILED);
     }
//--- bind the arrays to the indicator buffers
   SetIndexBuffer(0,buff,INDICATOR_DATA);
   SetIndexBuffer(1,color_buff,INDICATOR_COLOR_INDEX);
//---- set the indicator values that will not be visible on the chart
   PlotIndexSetDouble(0,PLOT_EMPTY_VALUE,0);
//---
   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[])
  {
   ArraySetAsSeries(time,false);
//--- the loop for the bars that have not been handled yet
   for(int i=prev_calculated;i<rates_total;i++)
     {
      //--- 0 by default
      buff[i]=0;
      color_buff[i]=0; // red color by default
      //--- check if any data is still present
      if(ind<size)
        {
         for(int j=ind;j<size;j++)
           {
            //--- if the dates coincide, the value from the file is used
            if(time[i]==time_buff[j])
              {
               //--- receive the price
               buff[i]=close_buff[j];
               //--- if the current price exceeds the previous one, the color is blue
               if(buff[i-1]>buff[i])
                  color_buff[i]=1;
               //--- increase the counter
               ind=j+1;
               break;
              }
           }
        }
     }
//--- return value of prev_calculated for next call
   return(rates_total);
  }

See also

Real types (double, float), FileReadDouble, FileWriteFloat


Updated: 2015.12.03