title: Java return statement confusion
body: <p>I just want to ask, what is the meaning to (--a,b)? Can somebody explain to me.
  Currently i just want to trace the calculation manually, but i was stuck.</p>
  
  <p>This part of the code:</p>
  
  <blockquote>
    <p>else if (a%2 == 0)
      return (-a) * b  + print_it(--a, b);</p>
  </blockquote>