title: Why is $a + ++$a == 2?
body: <p>If I try this:</p>
  
  <pre><code>$a = 0;    
  echo $a + ++$a, PHP_EOL;
  echo $a;
  </code></pre>
  
  <p>I get this output:</p>
  
  <pre><code>2
  1
  </code></pre>
  
  <p>Demo: <a href="http://codepad.org/ncVuJtJu">http://codepad.org/ncVuJtJu</a></p>
  
  <h3>Why is that?</h3>
  
  <p>I expect to get this as an output:</p>
  
  <pre><code>1
  1
  </code></pre>
  
  <h3>My understanding:</h3>
  
  <pre><code>$a = 0;                    // a === 0    
  echo $a + ++$a, PHP_EOL;   // (0) + (0+1) === 1
  echo $a;                   // a === 1
  </code></pre>
  
  <p>But why isn't that the output?</p>