View Compilation Error

0_0_4938831_30402.cpp: In constructor `node<T>::node()':
0_0_4938831_30402.cpp:8: error: `NULL' undeclared (first use this function)
0_0_4938831_30402.cpp:8: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_4938831_30402.cpp: In constructor `node<T>::node(const T&)':
0_0_4938831_30402.cpp:9: error: `NULL' undeclared (first use this function)
0_0_4938831_30402.cpp: In function `void OutOfRange()':
0_0_4938831_30402.cpp:36: error: `cout' undeclared (first use this function)
0_0_4938831_30402.cpp:36: error: `endl' undeclared (first use this function)
0_0_4938831_30402.cpp: In member function `void DLinkList<T>::traverse()':
0_0_4938831_30402.cpp:145: error: `cout' undeclared (first use this function)
0_0_4938831_30402.cpp:152: error: `endl' undeclared (first use this function)