title: right operand of comma operator has no effect std::cout
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/5665611/why-does-this-code-produce-a-warning-referring-to-the-comma-operator">Why does this code produce a warning referring to the comma operator?</a>  </p>
  </blockquote>
  
  
  
  <p>Why i get this warning while trying to compile this example in gcc?</p>
  
  <pre><code>#include &lt;iostream&gt;
  
  int main()
  {
     std::cout &lt;&lt; "str" &lt; 0;
  }
  </code></pre>
  
  <blockquote>
    <p>warning: right operand of comma operator has no effect
    [-Wunused-value]</p>
  </blockquote>