Borderou de evaluare (job #482726)

Eroare de compilare: user.cpp:9:5: error: 'null_type' was not declared in this scope user.cpp:9:5: note: suggested alternative: /usr/include/c++/4.6/ext/typelist.h:57:10: note: '__gnu_cxx::typelist::null_type' user.cpp:12:38: error: template argument 2 is invalid user.cpp:12:51: error: invalid type in declaration before ';' token user.cpp: In function 'int main()': user.cpp:24:15: error: request for member 'insert' in 's', which is of non-class type 'ordered_set {aka int}' user.cpp:27:24: error: request for member 'find_by_order' in 's', which is of non-class type 'ordered_set {aka int}' user.cpp:27:41: error: unable to deduce 'auto' from '<expression error>'