title: PowerShell: Why is this while() statement looping for ever?
body: <p>Why is the following while statement looping for ever? I want to break out after the users has entered "yes" or "no". Everything else should keep him in the input loop. </p>
  
  <pre><code>while ($input -ne "yes" -or $input -ne "no") {
      $input = Read-Host "Ready to process? [yes|no]"
  
      switch ($input) {
          yes { 
              write-host "yes"    
          }
  
          no  { 
              write-host "no" 
          }
  
          default { 
              write-host "input not understood" 
  
          }
      }  
  }
  </code></pre>