title: C++ Problem : "Error external 'C::C()' referenced from C:\C++\CRP.OBJ"
body: <p>I'm trying to get this:</p>
  
  <pre><code>//C.h
  #ifndef C_H
  #define C_H
  #include "c.h"
  
  class C
  {
      public:
          C();
          int function(int, int);
  };
  #endif
  </code></pre>
  
  <p>which is defined in this:</p>
  
  <pre><code>//c.cpp
  #include "c.h"
  C::C()
  {
  }
  int C::function(int a, int b)
  {
      return a * b;
  }
  </code></pre>
  
  <p>to work in this:</p>
  
  <pre><code>//crp.cpp
  #include &lt;iostream&gt;
  #include "c.h"
  
  void main(void)
  {
      C a;
      std::cout &lt;&lt; a.function(1, 2);
  }
  </code></pre>
  
  <p>but I get two errors</p>
  
  <p>Error: Unresolved external 'C::C()' referenced from C:\C++\CRP.OBJ</p>
  
  <p>Error: Unresolved external 'C::function(int, int)' referenced from C:\C++\CRP.OBJ</p>
  
  <p>I'm really stuck. Help v. much appreciated! </p>
  
  <p>EDIT:</p>
  
  <p>Thank you for your replies,</p>
  
  <p>I'm using Borland C++ 5.5.1 for Win32, via the command line, I'm not actually sure what a linker is, this is the first time I've tried doing this.</p>