Mine

static private FileStream freader;
    static private StreamReader reader;
    static private StreamWriter writer;
    static private int fileContents;

    static void Main()
    {
        string counter_file = "counter.txt";
        try
        {
            freader = new FileStream(counter_file, FileMode.Open, FileAccess.ReadWrite);
            reader = new StreamReader(freader);

            fileContents = Int32.Parse(reader.ReadToEnd());
            reader.Close();

        Console.WriteLine(fileContents);
                fileContents++;
        Console.WriteLine(fileContents);

            writer = new StreamWriter(counter_file);
            writer.Write(fileContents);
            writer.Flush();
            writer.Close();
            freader.Close();