title: What is \uffff in c#
body: <p>when I'm trying to do </p>
  
  <pre><code>char c = (char)-1;
  </code></pre>
  
  <p>I'm getting compiler error stating that Constant value '-1' cannot be converted to a 'char' </p>
  
  <p>which leads me thinking that this is an invalid conversion. But when I do this in runtime im getting back the character <code>'\uffff'</code>. </p>
  
  <p>Out of curiosity what is that character and why does the compiler not like it?</p>