title: A weird thing in c# Encoding
body: <p>I convert a <code>byte array</code> to a <code>string</code> , and I convert this <code>string</code> to <code>byte array</code>. 
  these two byte arrays are different.</p>
  
  <p>As below:</p>
  
  <pre><code>byte[] tmp = Encoding.ASCII.GetBytes(Encoding.ASCII.GetString(b));
  </code></pre>
  
  <p>Suppose b is a byte array. </p>
  
  <blockquote>
    <p>b[0]=3, b[1]=188, b[2]=2 //decimal system</p>
  </blockquote>
  
  <p>Result:</p>
  
  <blockquote>
    <p>tmp[0]=3, tmp[1]=63, tmp[2]=2</p>
  </blockquote>
  
  <p>So that's my problem, what's wrong with it?</p>