title: Why can I use printf() when including iostream?
body: <p>This piece of codes works fine even with minGW compiler under C++11 standards:</p>
  <pre><code>#include &lt;iostream&gt;
  
  int main(int argc, char const *argv[])
  {
      printf(&quot;haha&quot;);
      return 0;
  }
  </code></pre>
  <p>Why should this work? I didn't include <code>stdio.h</code> but I can use functions like <code>printf()</code> and <code>rand()</code>. Are they included in <code>iostream</code>? At least I didn't find them included. If you say that it's included in <code>iostream</code>, show me the evidence.</p>