/*------------------------------------------------
Write strings to log file example program by techbricks.nl
This program creates a file named "tachometer0-0.csv" (csv file, comma seperated file)
If this file already exists it creates a file that not exists (increments the file number) "tachometer<file number>-0.csv"
This file is 1024 bytes long.
You can write strings to this file. Every string (line) is ended with a EOL (end of line).
When this file is full a new file is created. The name of that file is "tachometer<file number>-<part number>.csv"
(the file part number is incremented)
This program will continue writing to file and creating new files until you press the orange button or the NXT runs out of memory.
Important: If your NXT memory is full, use the Bicxcc file explorer to (re)move the files from your NXT!!
24 september 2009
NXC (build on NXC/NBC firmware version 1.28, Bricxcc 3.3 - build 3.3.7.20, check http://bricxcc.sourceforge.net/nbc/ for more info)
Read more about it at www.techbricks.nl/My-NXT-projects/nxttachometerspeedcomputer.html
Use this demo program to display digits for your own applications....
-------------------------------------------------*/
  unsigned int result;
  byte fileHandle;
  short fileSize;
  short bytesWritten;
  string read;
  string write;
  int filenumber,filepart;
  string filename,sfilenumber,sfile,sfilepart;

/*-------------------------------------------------
Create a log file named "tachometer0-0.csv". If a file with that name already exists then it creates an other file.
It increments the file number: "tachometer<file number>-0.csv"
This file is 1024 bytes long.
---------------------------------------------------*/
void InitWriteToFile()
  {
  filenumber=0;
  filepart=0;
  filename="tachometer0-0.csv";
  result=CreateFile(filename, 1024, fileHandle);
  // check if the file already exists
  while (result==LDR_FILEEXISTS)
     {
      CloseFile(fileHandle);
      filenumber=filenumber+1;
      filename=NumToStr(filenumber);
      filename=StrCat("tachometer",filename,"-0.csv");
      result=CreateFile(filename, 1024, fileHandle);
      }
  // play a tone every time a file is created
  PlayTone(TONE_B7, 5);
  write = "RPM (last second),RPM (last minute)";
  WriteLnString(fileHandle,write, bytesWritten);
  }

/*-------------------------------------------------
You can write strings to this file. Every string (line) is ended with a EOL (end of line).
When this file is full a new file is created. The name of that file is "tachometer<file number>-<part number>.csv"
(the file part number is incremented)
---------------------------------------------------*/
void   WriteToFile(string write)
  {
  // write string to file
  result=WriteLnString(fileHandle,write, bytesWritten);
  // if the end of file is reached, close the file and create a new part
  if (result==LDR_EOFEXPECTED)
    {
    // close the current file
    CloseFile(fileHandle);
    // create the next file name
    filepart=filepart+1;
    sfilenumber=NumToStr(filenumber);
    sfilepart=NumToStr(filepart);
    // filename = "tachometer"+<file number>+"-"+<file part>+".csv"
    filename=StrCat("tachometer",sfilenumber,"-",sfilepart ,".csv");
    // delete the file if it exists
    DeleteFile(filename);
    // create a new file
    CreateFile(filename, 1024, fileHandle);
    // play a tone every time a file is created
    PlayTone(TONE_B7, 5);
    WriteLnString(fileHandle,write, bytesWritten);
    }
  }

// Close the file
void StopWriteToFile()
  {
  // close the file
  CloseFile(fileHandle);
  }

task main()
{

string text,text1,text2;

//Create a new file
InitWriteToFile();

// Never ending loop until the orange button is pressed or the NXT runs out of memory
while (true<>ButtonPressed(BTNCENTER,false)&&(FreeMemory()>=2000))
  {
  // Create a random text
  text1=NumToStr(Random(9999));
  text2=NumToStr(Random(9999));
  text=StrCat(text1,",",text2,"," );
  
  // write the text to a file. The text will be end with a EOL
  WriteToFile(text);
  }
 // close the file
StopWriteToFile();

}