C++: Conflicts with a previous declaration?

I'm working on this assignment, and I keep getting an error for an apparently previously declared method. Here is the .h file: ``` #ifndef DLLIST_H #define DLLIST_H #include <iostream> #include <fstream> #include <cstddef> #include "DListNode.h" typedef int ItemType; class DLList { private: friend std::ostream & operator<< (std::ostream & out, DLList & other); int size; int * head; int * tail; void _copy(const DLList * toCopy); void _dealloc(); public: DLList(); DLList(const DLList & toCopy); ~DLList(); DLList & operator=(const DLList & toCopy); int size(); void append(ItemType item); void insert(int index, ItemType item); ItemType pop(int index); ItemType pop(); const DListNode & operator[] (int idx); }; std::ostream & operator<< (std::ostream & out, const DLList & d); #endif ``` The error is being triggered at `int size();`, saying it conflicts with a previous declaration. I know this normally would arise from me including this header file multiple times, but I just don't see where it is happening. These are the include statements for all the files in the project: ``` #include "DLList.h" // DLList.cpp ======================================= #include "DListNode.h" // DListNode.cpp ======================================= #include <iostream> // DListNode.h #include <fstream> #include <cstddef> ======================================= #include "DLList.h" // This is the main test file #include "DListNode.h" #include <iostream> ``` I can see that DListNode.h is technically being included twice, but nowhere is DLList.h included more than once. Am I just making a stupid mistake and not seeing it? (Probably the case). Thanks for any help!