What does this C++ code mean?
<p>What does the following C++ code mean?</p>

<pre><code>unsigned char a : 1; 
unsigned char b : 7;
</code></pre>

<p>I guess it creates two char a and b, and both of them should be one byte long, but I have no idea what the ": 1" and ": 7" part does. </p>
