title: xCode: Objective C: duplicate symbol error
body: <p>In file CarArray (without any extension) I have the array like that (this is a very simplified version):</p>
  
  <pre><code>NSString *cars[5][3] = {
      {@"1A", @"1B", @"1C"},
      {@"2A", @"2B", @"2C"},
      {@"3A", @"3B", @"3C"},
      {@"4A", @"4B", @"4C"},
      {@"5A", @"5B", @"5C"}
  }
  </code></pre>
  
  <p>Now I want to read the data from the array in multiple files so I simply use <code>#import "CarArray"</code></p>
  
  <p>And I use a loop to read the data. Then I get such an error:</p>
  
  <pre><code>duplicate symbol _cars in:
  /Users/Adam/Library/Developer/Xcode/DerivedData/Auto_Center-hgjlsqanvyynncgyfzuorxwchqov/Build/Intermediates/Auto Center.build/Debug-iphonesimulator/Auto Center.build/Objects-normal/i386/DetailViewController.o
  /Users/Adam/Library/Developer/Xcode/DerivedData/Auto_Center-hgjlsqanvyynncgyfzuorxwchqov/Build/Intermediates/Auto Center.build/Debug-iphonesimulator/Auto Center.build/Objects-normal/i386/ModelListViewController.o
  ld: 1 duplicate symbol for architecture i386
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  </code></pre>
  
  <p>How can I solve that problem?</p>