title: May I #include in .hpp files?
body: <p>I have a class called A, which has its <code>.cpp</code> and <code>.hpp</code> files. It depends on classes <code>B</code> and <code>C</code>. Now, I'm wondering, should I <code>#include B.hpp</code> and <code>#include C.hpp</code> in <code>A.cpp</code> or <code>A.hpp</code>? I think it would be beneficial for me to <code>#include</code> in the <code>A.hpp</code> file, because I'm creating a vector of <code>B*</code>'s, and I'm not sure that the compiler will know the correct size of <code>B</code> if I only forward declare it (so I couldn't pointer increment correctly)... By "forward declaration", I mean writing <code>class B;</code> and <code>class C;</code> in the beggining of <code>A.hpp</code>.</p>