title: Compile error: Undefined symbols: "_main", referenced from: start in crt1.10.5.o
body: <p>I have the following code:</p>
  
  <pre><code>#include &lt;iostream&gt;
  
  using namespace std;
  
  class testing{
     int test() const;
     int test1(const testing&amp; test2);
  };
  
  int testing::test() const{
     return 1;
  }
  
  int testing::test1(const testing&amp; test2){
     test2.test();
     return 1;
  }
  </code></pre>
  
  <p>after compilation, it gives me the following error:</p>
  
  <pre><code>Undefined symbols:
    "_main", referenced from:
        start in crt1.10.5.o
  ld: symbol(s) not found
  collect2: ld returned 1 exit status
  </code></pre>
  
  <p>Why is it complaining about main? Can't i declare main in another file and include this one?</p>
  
  <p>Thanks a lot!</p>