In file included from /in/call.cpp:1:
In file included from /in/dlist_impl.h:2:
In file included from /in/Compile/dlist.h:76:
/in/Compile/dlist_ins_impl.h:18:16: error: use of undeclared identifier 'NULL'
    np->prev = NULL;
               ^
/in/Compile/dlist_ins_impl.h:20:20: error: use of undeclared identifier 'NULL'
    if(np->next == NULL)
                   ^
/in/Compile/dlist_ins_impl.h:32:13: error: use of undeclared identifier 'NULL'
        np->next = NULL;
                   ^
/in/Compile/dlist_ins_impl.h:35:20: error: use of undeclared identifier 'NULL'
    if(np->prev == NULL)
                   ^
/in/Compile/dlist_ins_impl.h:57:17: error: use of undeclared identifier 'NULL'
    if(first == NULL)
                ^
/in/Compile/dlist_ins_impl.h:58:16: error: use of undeclared identifier 'NULL'
        last = NULL;
               ^
/in/Compile/dlist_ins_impl.h:60:23: error: use of undeclared identifier 'NULL'
        first->prev = NULL;
                      ^
/in/Compile/dlist_ins_impl.h:80:16: error: use of undeclared identifier 'NULL'
    if(last == NULL)
               ^
/in/Compile/dlist_ins_impl.h:81:17: error: use of undeclared identifier 'NULL'
        first = NULL;
                ^
/in/Compile/dlist_ins_impl.h:83:22: error: use of undeclared identifier 'NULL'
        last->next = NULL;
                     ^
/in/Compile/dlist_ins_impl.h:123:26: error: use of undeclared identifier 'NULL'
Dlist<T>::Dlist(): first(NULL), last(NULL)
                         ^
/in/Compile/dlist_ins_impl.h:123:38: error: use of undeclared identifier 'NULL'
Dlist<T>::Dlist(): first(NULL), last(NULL)
                                     ^
/in/Compile/dlist_ins_impl.h:128:40: error: use of undeclared identifier 'NULL'
Dlist<T>::Dlist(const Dlist &l): first(NULL), last(NULL)
                                       ^
/in/Compile/dlist_ins_impl.h:128:52: error: use of undeclared identifier 'NULL'
Dlist<T>::Dlist(const Dlist &l): first(NULL), last(NULL)
                                                   ^
In file included from /in/call.cpp:1:
/in/dlist_impl.h:11:16: error: redefinition of 'isEmpty'
bool Dlist<T>::isEmpty() const {
               ^
/in/Compile/dlist_ins_impl.h:7:16: note: previous definition is here
bool Dlist<T>::isEmpty() const
               ^
In file included from /in/call.cpp:1:
/in/dlist_impl.h:17:16: error: redefinition of 'insertFront'
void Dlist<T>::insertFront(T *op) {
               ^
/in/Compile/dlist_ins_impl.h:13:16: note: previous definition is here
void Dlist<T>::insertFront(T *op)
               ^
In file included from /in/call.cpp:1:
/in/dlist_impl.h:32:16: error: redefinition of 'insertBack'
void Dlist<T>::insertBack(T *op) {
               ^
/in/Compile/dlist_ins_impl.h:28:16: note: previous definition is here
void Dlist<T>::insertBack(T *op)
               ^
In file included from /in/call.cpp:1:
/in/dlist_impl.h:47:15: error: redefinition of 'removeFront'
T * Dlist<T>::removeFront() {
              ^
/in/Compile/dlist_ins_impl.h:43:14: note: previous definition is here
T *Dlist<T>::removeFront()
             ^
In file included from /in/call.cpp:1:
/in/dlist_impl.h:62:15: error: redefinition of 'removeBack'
T * Dlist<T>::removeBack() {
              ^
/in/Compile/dlist_ins_impl.h:66:14: note: previous definition is here
T *Dlist<T>::removeBack()
             ^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.
/in/Compile/Makefile:39: recipe for target 'buildCall' failed
make: *** [buildCall] Error 1