<p>I've seen a lot of questions around that use improperly the expression "C/C++".
The reasons in my opinion are: </p>

<ul>
<li>Newbie C and C++ programmers probably don't understand the difference between the two languages.</li>
<li>People don't really care about it since they want a generic, quick and "dirty" answer</li>
</ul>

<p>While C/C++ could sometimes be interpreted as "either C or C++", I think it's a big error. C and C++ offer different approaches to programming, and even if C code can be easily implemented into C++ programs I think that referring to two separate languages with that single expression ( C/C++ ) is wrong.<br /></p>

<p>It's true that some questions can be considered either as C or C++ ones, anyway. 
What do you think about it?</p>

C/C++ is a holdout from the early days of C++, where they were much more similar than they were today. It's something that wasn't really wrong at first, but is getting more-so all the time.
The basic structure is similar enough that most simple questions do still work between the two, though. There is an entire Wikipedia article on this topic:
http://en.wikipedia.org/wiki/Compatibility_of_C_and_C%2B%2B
The biggest fallacy that comes from this is that because someone is well-versed in C, they will be equally good at C++.