title: Cannot create an instance of the static class 'System.Tuple'
body: <p>I am very new to the language. This code is giving me error:</p>
  
  <blockquote>
    <p>Cannot create an instance of the static class 'System.Tuple' </p>
  </blockquote>
  
  <pre><code>Operator '!=' cannot be applied to operands of type 'bool' and 'int'
  </code></pre>
  
  <p>I don't know  what I am doing wrong. Can some tell me what is wrong  </p>
  
  <pre><code>using(StreamReader rdr = new StreamReader("fileName"))
  {
      StringBuilder sb = new StringBuilder();
      Int32 nc = 0;
      Char c;
      Int32 lineNumber = 0;
      while( (nc == rdr.Read() !=-1 ))
      {
          c = (Char)nc;
          if( Char.IsWhiteSpace(c) )
          {
              if( sb.Length &gt; 0 )
              {
                  yield return new Tuple( sb.ToString(), lineNumber );
                  sb.Length = 0;
              }
  
              if( c == '\n' ) lineNumber++;
          } 
          else 
          {
              sb.Append( c );
          }
      }
      if( sb.Length &gt; 0 ) yield return new Tuple( sb.ToString(), lineNumber );
  }   
  </code></pre>