title: G++ -I option for compiling program
body: <p>Here is a little problem that cannot be resolved by me such a Linux program newbie.</p>
  
  <p>Now I have a main.cpp program which need to be compiled, there is a </p>
  
  <pre><code>#include "Down.h"
  </code></pre>
  
  <p>in the front of file.</p>
  
  <p>Actually, this header file exist in the other directory, which locates at 
  <code>../../../include</code> 
  directory. Besides, some other header files needed by Down.h also locate at this ../../../include directory.</p>
  
  <p>Here is the problem, I compile main.cpp with command </p>
  
  <pre><code>g++ -I /../../../include main.cpp
  </code></pre>
  
  <p>However, it gives lots of error info which means it is not correct to be done like this.</p>
  
  <p>Should I also change the include declaration into this one?</p>
  
  <pre><code>#include "../../../include/DownConvert.h"
  </code></pre>
  
  <p>May you please leave me with some advice? Thanks.</p>
  
  <h2>Edit:</h2>
  
  <p>After using <code>g++ -I ../../../include main.cpp</code>, I get the following errors:</p>
  
  <pre><code>$ g++ -I ../../../include main.cpp 
  
  In file included from ../../../include/DownConvert.h:98,
  from main.cpp:92: ../../../include/ResizeParameters.h:4:22: error:
  TypeDefs.h: No such file or directory 
  
  In file included from /usr/include/c++/4.4/bits/stl_algo.h:61, 
  from /usr/include/c++/4.4/algorithm:62, 
  from ../../../include/H2 
  </code></pre>