title: Unresolved External Symbol with my Config Class (C++)
body: <p>I have looked at so many threads about this topic and none of them have helped. I still cannot figure out what I am doing wrong. Please help!</p>
  
  <p>I am getting this error:</p>
  
  <pre><code>main.obj:-1: error: LNK2019: unresolved external symbol "public: __thiscall Config::Config(class std::basic_string&lt;char,struct std::char_traits&lt;char&gt;,class std::allocator&lt;char&gt; &gt;)" (??0Config@@QAE@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) referenced in function _main
  </code></pre>
  
  <p>and here is what I have codewise. I stripped everything from the code to try and figure this out; it's extremely simple.</p>
  
  <p>My Config.h file</p>
  
  <pre><code>#ifndef CONFIG_H
  #define CONFIG_H
  
  #include &lt;string&gt;
  
  class Config{
  public:
       Config(std::string file_name);
  };
  
  #endif
  </code></pre>
  
  <p>and here is my Config.cpp file</p>
  
  <pre><code>//Config class
  #include "Config.h"
  #include &lt;string&gt;
  
  Config::Config(std::string file_name){
      //Do stuff
  }
  </code></pre>
  
  <p>and here is where I try to use it</p>
  
  <pre><code>Config c("test");
  </code></pre>
  
  <p>I cannot figure this out for the life of me even after like an hour of reading through articles and threads.</p>