/in/p2.cpp: In function 'opaque_list* chop(list_t, unsigned int)':
/in/p2.cpp:122:7: error: expected primary-expression before 'unsigned'
  if ( unsigned int (size(list)) <= n)
       ^~~~~~~~
/in/p2.cpp:122:7: error: expected ')' before 'unsigned'
/in/p2.cpp:126:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^