[RESOLVED] Reading text file by character

[WinnitBaker]

Hi guys,

I am trying to read a text file, filter out the tabs and replace them with commas. For some reason my code will just not do this!! I am new to this site and still doing my degree so still novice programmer. Many thanks

[WinnitBaker]

Below is the function in which the text file is being read -
private void Convert()
{
StreamReader sr = new StreamReader(ofd1.FileName);
StreamWriter sw = new StreamWriter(sfd1.FileName);
string line = "";
char c;

while((line = sr.ReadLine()) != null)
{
c = (char)sr.Read();

if (c == '\t')
{
//MessageBox.Show("char found");
c = ',';
sw.Write(c);
sw.Flush();
}
sw.WriteLine(line);
}


sr.Close();
sw.Close();
MessageBox.Show("Convertion complete");
}

[Jim_Auricman]

You might want to try reading in using a BinaryReader and writing out using BinaryWriter.
BinaryReader r = new BinaryReader(fs);

binWriter = new BinaryWriter(File.Open(outfilename, FileMode.Create));
binWriter.Write(input_char);

[Silent Sojourner]

int t
while((t = sr.Read()) > -1)
{
   c = (char)t;

if (c == '\t')
{

[Mutant_Fruit]

You might want to try reading in using a BinaryReader and writing out using BinaryWriter.
BinaryReader r = new BinaryReader(fs);

binWriter = new BinaryWriter(File.Open(outfilename, FileMode.Create));
binWriter.Write(input_char);

Why would you read a text file using a BinaryReader? If you're comparing characters you need to be encoding aware which means you need to convert the raw bytes into a character using either a StreamReader with the correct encoding set or by reading into a byte[] and using the System.Text.Encoding classes to do it. The former is by far the easiest.

[WinnitBaker]

Cheers for you help there was no need for a binary reader, i recieved no emals saying my forum had been responded to so I ended up sorting it myself cheers for your help Silent Sojourner your answer was similar to mine except i used peek i ended up with -
while((sr.Peek() >= 0))
{
char c = (char)sr.Read();
if (c == '\t')
{
c = ',';
}
sw.Write((char)c); //rewrite all characters
}

[DataMiser]

Reading and writing one character at a time would be the slowest possible way to do this. I would read the entire file at once into a string then use replace to replace all the tabs with commas then write the resulting string to disk all at once. Should be at least 100 times faster.

[Silent Sojourner]

well it depends. what if the file size is huge, say, 2gb?

[DataMiser]

If it were that big then reading all at once would be a lot faster still. Most systems today have at least 4 gigs of ram and ram is much faster than disk and a single read is much faster than 1000s of reads.

[WinnitBaker]

I understand how reading and writing it character by character could be a bit naff in some circimstances. But the aim of this program was to demonstrate the use of threads and by reading a large text file by character demonstrated that we needed another thread. cheers