user3311: I am trying to write a class/function that I think I will be using often in my Arduino IDE, I know the code but where should i save the file so that the IDE picks it up without a full directory address in the #include line, as you may guess I'm a little new to this....

user1407: If you think you will be reusing this code frequently, you might want to make a library as suggested by Joachim. Your library can then be added to any sketch you write using a #include statement. 
The arduino website has a nice guide on writing libraries, check it out here.
If you would just like to include your header file in a sketch without writing a library, placing the header file in the same directory as your sketch should compile if you use #include "header_file_name.h".

3311: <p>I am trying to write a class/function that I think I will be using often in my Arduino IDE, I know the code but where should i save the file so that the IDE picks it up without a full directory address in the #include line, as you may guess I'm a little new to this....</p>
 1407: <p>If you think you will be reusing this code frequently, you might want to make a library as suggested by Joachim. Your library can then be added to any sketch you write using a <code>#include</code> statement. </p>

<p>The arduino website has a nice guide on writing libraries, check it out <a href="http://arduino.cc/en/Hacking/LibraryTutorial" rel="nofollow">here</a>.</p>

<p>If you would just like to include your header file in a sketch without writing a library, placing the header file in the same directory as your sketch should compile if you use <code>#include "header_file_name.h"</code>.</p>
