title: Should we include a macro(#define) in both .h & .cpp files
body: <p>If i use them in both the files. 
  Going with the term "macro" in c++ it's just a replacement mechanism(doesn't know anything about c++ structure) that happens in pre-compilation stage. </p>
  
  <p>Is this the reason that i should define macro(#define) in both the files or doesn't need to do that or am i missing anything.?</p>