Do you need to explicitly include headers that other headers already include themselves?
<p>Given a header file <code>foo.h</code>:</p>

<pre class="lang-cpp prettyprint-override"><code>#include &lt;bar&gt;

// ...
</code></pre>

<p>And a file <code>baz.cpp</code>:</p>

<pre class="lang-cpp prettyprint-override"><code>#include "foo.h"

// ...
</code></pre>

<p>Do you need to explicitly include the <code>bar</code> header into <code>baz.cpp</code> in order to use it? Or can you just start using it since it's included in <code>foo.h</code>?</p>