How to write a pretty-printer for std::list<*> in C++?

Question

I can easily write a pretty-printer for std::vector<*> like this:

template <typename T>
std::ostream &operator<<(std::ostream &origin, const std::vector<T> &vec){
    origin << "{ ";
    for(int i = 0; i < vec.size(); i++)
        origin << vec[i] << " ";
    origin << "}";
    return origin;
}

But when I wrote a pretty-printer for std::list<*> similarly:

template <typename T>
std::ostream &operator<<(std::ostream &origin, const std::list<T> &lis){
    origin << "[ ";
    for(std::list<T>::const_iterator it = lis.begin(); it != lis.end(); it++)
        origin << *it << " ";
    origin << "]";
    return origin;
}

gcc reported:

../main.cpp: In function ‘std::ostream& operator<<(std::ostream&, const std::list<T>&)’:
../main.cpp:13:6: error: need ‘typename’ before ‘std::list<T>::const_iterator’ because ‘std::list<T>’ is a dependent scope
  for(std::list<T>::const_iterator it = lis.begin(); it != lis.end(); it++)
      ^
../main.cpp:13:35: error: expected ‘;’ before ‘it’
  for(std::list<T>::const_iterator it = lis.begin(); it != lis.end(); it++)
                                   ^
../main.cpp:13:53: error: ‘it’ was not declared in this scope
  for(std::list<T>::const_iterator it = lis.begin(); it != lis.end(); it++)
                                                     ^
../main.cpp: In instantiation of ‘std::ostream& operator<<(std::ostream&, const std::list<T>&) [with T = int; std::ostream = std::basic_ostream<char>]’:
../main.cpp:24:15:   required from here
../main.cpp:13:51: error: dependent-name ‘std::list<T>::const_iterator’ is parsed as a non-type, but instantiation yields a type
  for(std::list<T>::const_iterator it = lis.begin(); it != lis.end(); it++)
                                                   ^
../main.cpp:13:51: note: say ‘typename std::list<T>::const_iterator’ if a type is meant
make: *** [main.o] Error 1

Could you help me writing a working pretty-printer for std::list<*> and explain the meaning of the error message to me please?