/in/node.cpp:17:34: error: default argument given for parameter 2 of 'Node::Node(int, int)' [-fpermissive]
 Node::Node(int _value, int _n = 2){
                                  ^
In file included from /in/node.cpp:1:0:
/in/node.h:23:5: note: previous specification in 'Node::Node(int, int)' here
     Node(int _value, int _n = 2);
     ^~~~
/in/node.cpp: In member function 'bool Node::contain(Node*)':
/in/node.cpp:50:1: error: no return statement in function returning non-void [-Werror=return-type]
 }
 ^
/in/node.cpp: In member function 'Node& Node::operator[](int)':
/in/node.cpp:60:1: error: no return statement in function returning non-void [-Werror=return-type]
 }
 ^
cc1plus: all warnings being treated as errors