title: 'Object' has not been declared error
body: <p>I'm new to c++ coming from Java so I'm not sure what I'm doing wrong here
  the following line in <code>person.h</code> is giving me the error <code>Transaction has not been declared</code>.</p>
  
  <pre><code>void pay(Transaction transaction);
  </code></pre>
  
  <p>I have a Transaction object, do I have to declare / include it in the <code>person.h</code> file somewhere?</p>
  
  <p>here is my <code>person.h</code> source</p>
  
  <pre><code>#ifndef PERSON_H_
  #define PERSON_H_
  
  #include "Transaction.h"
  
  using std::string;
  
  class Person {
  public:
  
      class Transaction;
  
      Person();
      virtual ~Person();
      void pay(Transaction* transaction);
  };
  
  #endif /* PERSON_H_ */
  </code></pre>