title: type or namespace name "StreamReader" could not be found
body: <p>I am working on StreamReader in C#. I am getting the error</p>
  
  <blockquote>
    <p>"The type or namespace name "StreamReader" could not be found"</p>
  </blockquote>
  
  <p>I have no idea what I am doing wrong. </p>
  
  <pre><code>using System.IO;
  using System;
  class Perfect
  {
  static void Main()
      {
      string filename = @"marks.cvs";
      StreamReader sr = new StreamReader(filename);
      string line = sr.ReadLine();
      Console.WriteLine(line);    
      sr.Close();
      }
  }
  </code></pre>