title: Using Definitions in C Header Files?
body: <p>I'm currently learning the <strong>C</strong> programming language (coming from Java) and I'm a bit confused as to how to define a macro.</p>
  
  <p>In order for other code to use the macro, the header file must have it.  But if I define the macro in the header file, then the source file can't use it.  Do I have to define it in both or do I have to #include the source file's own header file?</p>