how to modify data in csv file?

[Jinsong Zhang]

I have some codes:

===============================================
int start()
{

int songrecord;
songrecord=FileOpen("_record.csv", FILE_CSV|FILE_WRITE|FILE_READ,',');
if(songrecord<=0)return;

int FA_id=1114444;

int myFA;
FileWrite(songrecord,"1114443",0);
FileWrite(songrecord,"1114444",0);
FileWrite(songrecord,"1114445",0);
FileSeek(songrecord, 0, SEEK_SET);
while(!FileIsEnding(songrecord))
{

myFA=StrToInteger(FileReadString(songrecord));

if(myFA==FA_id){
int pos=FileTell(songrecord);
Alert(pos);
FileSeek(songrecord, pos-2, SEEK_SET);
FileWrite(songrecord,6.6);

Alert(GetLastError() );
break;
}
}

FileClose(songrecord);
}

============================================

I want it export as:

1114443 0
1114444 6.6
1114445 0

but is export as:

1114443 0
1114444 6.6
4445 0

How can I do?