title: If I have an include statement in header, do I need to put it in source?
body: <p>To further the question from <a href="https://stackoverflow.com/questions/3943352/where-to-put-include-statements-header-or-source">Where to put include statements, header or source?</a>:</p>
  
  <p>If I already have an include statement in the header, eg #include, do I still need to put it inside the source file? I am able to compile with #include in both file, and it's fine when I've dropped #include from source file.</p>
  
  <p>So which is more appropriate, or it doesn't really matters?</p>