title: C in Xcode cs50.h issues
body: <p>I am trying to follow along with the cs50 course online in Xcode. I have imported the cs50 header file. I can use <code>printf</code> but I am still getting errors when calling <code>GetInt</code>. Error reads: </p>
  
  <pre><code>Apple Mach-O Linker (Id) Error "_GetInt", referenced from:
  </code></pre>
  
  <p>Any help is of course greatly appreciated. Thank you.</p>