int count = 0;
    string line;
    try
    {
      StreamReader sr = new StreamReader(filePath);
      line = sr.ReadLine();
      while (line != null)
      {
       count++;
        line = sr.ReadLine();
      }
      sr.Close();
    }
    catch (Exception ex)
    {
      Console.WriteLine(ex);
    }

    string uName;
    Console.WriteLine("Please, enter your name.");
    uName = Console.ReadLine();
 
    try
    {
      string filePath = Path.Combine(
        AppDomain.CurrentDomain.BaseDirectory,
        "HelloWorld.txt"
      );
      // This string contains the path for the file we create.
      StreamWriter sw = new StreamWriter(filePath);
      // We create the file
      sw.WriteLine("Hello " + uName);
      sw.Close();
      Console.WriteLine("Check out " + filePath + "!");
    }
    catch (Exception e)
    {
      Console.WriteLine("Exception: " + e.Message);
    }

    string fName,
      filePath;
    do
    {
      Console.WriteLine("Enter a file name.");
      fName = Console.ReadLine();
      filePath = Path.Combine(
        AppDomain.CurrentDomain.BaseDirectory,
        fName
      );
    } while (
      !fName.EndsWith(".txt")
      || fName.StartsWith(".")
      || File.Exists(filePath)
    );
    try
    {
      StreamWriter sw = new StreamWriter(filePath);
      for (int i = 1; i <= 1000000; i++)
        sw.WriteLine(i);
      sw.Close();
      Console.WriteLine("Check out " + filePath + "!");
    }
    catch (Exception e)
    {
      Console.WriteLine("Exception: " + e.Message);
    }

    string line;
    int number;
    int maxSoFar;
    try
    {
      StreamReader sr = new StreamReader(filePath);
      line = sr.ReadLine();
      if (int.TryParse(line, out number))
      {
        maxSoFar = number;
      }
      else
      {
        throw new ArgumentException(
          "File contains string that is not a number."
        );
      }
      while (line != null)
      {
        if (int.TryParse(line, out number))
        {
          if (maxSoFar < number)
          {
            maxSoFar = number;
          }
        }
        else
        {
          throw new ArgumentException(
            "File contains string that is not a number."
          );
        }
        line = sr.ReadLine();
      }
      Console.WriteLine(
        "The maximum number in the file is "
          + maxSoFar
          + "."
      );
    }
    catch (Exception e)
    {
      Console.WriteLine("Exception: " + e.Message);
    }

      double number;
      double sum = 0;
      int counter = 0;
      double average;
      try
      {
        // Opening file
        StreamReader sr = new StreamReader(filePathP);
        // Reading first line
        string line = sr.ReadLine();
 
        // Looping through the file until we
        // reach the end, or read the word
        // "STOP" on its own line.
        while (line != null && line != "STOP")
        {
          // We test if the line contains a double.
          if (double.TryParse(line, out number))
          {
            sum += number;
            counter++;
          }
          // We read the next line.
          line = sr.ReadLine();
        }
        sr.Close();
      }
      catch { }
      // if to prevent division by 0.
      if (counter != 0)
      {
        average = sum / counter;
      }
      else
      {
        average = -1;
      }

    try
    {
      StreamReader sw = new StreamReader(filePath);
      string cLine = sw.ReadLine();
      decimal amount;
      while (cLine != null)
      {
        if (cLine[0] != '%')
        {
          if (decimal.TryParse(cLine, out amount))
          {
            Console.WriteLine($"{amount:C}");
          }
          else
          {
            Console.WriteLine(cLine);
          }
        }
        cLine = sw.ReadLine();
      }
    }
    catch
    {
      Console.WriteLine("An error was thrown.");
    }

    string filePath = Path.Combine(
      AppDomain.CurrentDomain.BaseDirectory,
      "TextTruncate.txt"
    );
    Console.WriteLine("Enter a string.");
    string uString = Console.ReadLine();
 
    const int MAXWIDTH = 40;
 
    try
    {
      StreamWriter sw = new StreamWriter(filePath);
      while (uString.Length > MAXWIDTH)
      {
        sw.WriteLine(uString.Substring(0, MAXWIDTH));
        uString = uString.Substring(MAXWIDTH);
      }
      sw.WriteLine(uString);
      sw.Close();
    }
    catch (Exception e)
    {
      Console.WriteLine("Exception: " + e.Message);
    }

using System;
using System.IO;
 
class Program
{
  static void Main()
  {
 
    string filePath = Path.Combine(
      new DirectoryInfo(
        Directory.GetCurrentDirectory()
      ).ToString(),
      "Program.cs"
    );
    
    /*
     * On older versions, you may need to use the following instead, 
     * as the program is executed in /bin/Debug, we need to go
     * two folders up, where Program.cs is located: note the ".Parent"
     * bits in the code that follows.
     */
    
    /*
    
    string filePath = Path.Combine(
      new DirectoryInfo(
        Directory.GetCurrentDirectory()
      ).Parent.Parent.ToString(),
      "Program.cs"
    );
    
    */
    
    if (!File.Exists(filePath))
    {
      Console.WriteLine(
        "There seems to be an issue. Impossible to locate Program.cs"
      );
    }
    else
    {
      Console.WriteLine("Program.cs located, processing.");
      string line;
      string[] words;
      int wCount = 0;
      try
      {
        StreamReader sr = new StreamReader(filePath);
        line = sr.ReadLine();
        while (line != null)
        {
          words = line.Split(
            new string[] { " " },
            StringSplitOptions.RemoveEmptyEntries
          );
          wCount += words.Length;
          line = sr.ReadLine();
        }
        sr.Close();
        Console.WriteLine(
          "Your program contains " + wCount + " words!"
        );
        // Should display "Your program contains 121 words!"
      }
      catch (Exception e)
      {
        Console.WriteLine("Exception: " + e.Message);
      }
    }
  }
}

using System;
using System.IO;
 
class Program
{
  static void Main(string[] args)
  {
    Console.WriteLine("Enter a path");
    string path = Console.ReadLine();
    if (File.Exists(path))
    {
      Console.WriteLine(
        "Now displaying file at " + path + "."
      );
      try
      {
        StreamReader sr = new StreamReader(path);
        string cLine = sr.ReadLine();
        while (cLine != null)
        {
          Console.WriteLine(cLine);
          cLine = sr.ReadLine();
        }
        sr.Close();
        Console.WriteLine("Done displaying file.");
      }
      catch
      {
        Console.WriteLine(
          "There was an error opening your file."
        );
      }
    }
    else
    {
      Console.WriteLine(
        "Now creating a file at "
          + path
          + ".\n Enter your text, one line at a time. When done, type \"!DONE!\" (without the quotes), then enter."
      );
      try
      {
        StreamWriter sw = new StreamWriter(path);
        string uInput = Console.ReadLine();
        while (uInput != "!DONE!")
        {
          sw.WriteLine(uInput);
          uInput = Console.ReadLine();
        }
        sw.Close();
        Console.WriteLine("File correctly written.");
      }
      catch
      {
        Console.WriteLine(
          "There was an error creating your file."
        );
      }
    }
  }
}