/in/foo.cc:19:1: error: prototype for 'PolyList::PolyList(PolyListNode&)' does not match any in class 'PolyList'
 PolyList::PolyList(PolyListNode &p)
 ^~~~~~~~
/in/foo.cc:15:2: error: candidate is: PolyList::PolyList(PolyList&)
  PolyList(PolyList &p);
  ^~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:50:14: error: no matching function for call to 'PolyList::PolyList(PolyListNode*&)'
  PolyList P(p);
              ^
/in/foo.cc:15:2: note: candidate: PolyList::PolyList(PolyList&)
  PolyList(PolyList &p);
  ^~~~~~~~
/in/foo.cc:15:2: note:   no known conversion for argument 1 from 'PolyListNode*' to 'PolyList&'