title: How to get string in system()
body: <p>I know I can see them by</p>
  <pre><code>std::cout &lt;&lt; system(&quot;my cmd&quot;);
  </code></pre>
  <p>but I want to get the cout stream.
  how can I get them like this?</p>
  <pre><code>std::string s; or char s[200];
  s &lt;&lt; system(&quot;my cmd&quot;);
  </code></pre>
  <p>It did't work. Shows <code>invalid operands to binary expression ('char [200]' and 'int')</code></p>