c# how do I count lines in a textfile

Question

any problems with doing this?

int  i = new StreamReader(\"file.txt\").ReadToEnd().Split(new char[] {\'\\n\'}).Length

Answer 1

Sure - it reads the entire stream into memory. It's terse, but I can create a file today that will fail this hard.

Read a character at a time and increment your count on newline.

EDIT - after some quick research If you want terse and want that shiny new generic feel, consider this:

public class StreamEnumerator : IEnumerable
{
    StreamReader _reader;

    public StreamEnumerator(Stream stm)
    {
        if (stm == null)
            throw new ArgumentNullException("stm");
        if (!stm.CanSeek)
            throw new ArgumentException("stream must be seekable", "stm");
        if (!stm.CanRead)
            throw new ArgumentException("stream must be readable", "stm");

        _reader = new StreamReader(stm);
    }

    public IEnumerator GetEnumerator()
    {
        int c = 0;
        while ((c = _reader.Read()) >= 0)
        {
            yield return (char)c;
        }
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }
}

which defines a new class which allows you to enumerate over streams, then your counting code can look like this:

StreamEnumerator chars = new StreamEnumerator(stm);
int lines = chars.Count(c => c == '\n');

which gives you a nice terse lambda expression to do (more or less) what you want.

I still prefer the Old Skool:

    public static int CountLines(Stream stm)
    {
        StreamReader _reader = new StreamReader(stm);
        int c = 0, count = 0;
        while ((c = _reader.Read()) != -1)
        {
            if (c == '\n')
            {
                count++;
            }
        }
        return count;
    }

NB: Environment.NewLine version left as an exercise for the reader