title: How to change from c99 to gcc in Xcode (Mac OS X)?
body: <p>I have a problem with my xcode. The thin is that my teacher can't execute my code just because I use C99. I've tried to change it but without any results, I have installed command line tool too whithout any result. Because of that I installed Netbeans IDE 7.4 and tried to program there. To test which standard the program used I tried with a loop <code>(int i = 0; i&lt; size; i++)</code> and the program complained which is a good sign. Now two days later I got the same problem with Netbeans too and I am really near to just jump off the course because of this issue. I'm late with my assignment just because my teacher doesn't accept my assignments written with c99 standard etc. 
  Someone who has have same issues and solved the problem? It doesn't really matter if it's on Netbeans or Xcode. I just wanna code. </p>
  
  <p>If you can't help me, whats the difference between c99 and c90 etc? I know that with the for loop but are there any other things that makes the code unexecutable?</p>
  
  <p>When I type gcc --version on the terminal I get this...</p>
  
  <p>Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
  Apple LLVM version 5.0 (clang-500.2.76) (based on LLVM 3.3svn)
  Target: x86_64-apple-darwin12.5.0
  Thread model: posix
  John-MacBook-Air:~ johnBlunt$ </p>
  
  <p>Here is my settings 
  <img src="https://i.stack.imgur.com/xlG49.png" alt="The compiler is a Apple LLVM 5.0. I don&#39;t know if it matters"></p>
  
  <p><img src="https://i.stack.imgur.com/aH7oI.png" alt="The C language dialect is c89 [-std= c89"></p>
  
  <p><img src="https://i.stack.imgur.com/HxPsm.png" alt="And I have set the settings to treat the warnings as errors"></p>