Sorting list < shared_ptr < foo > > using std::list::sort()

I have experienced some difficulty with sorting lists of type: list < shared_ptr < foo > > Here is the expected (sorted) program output: 424238335 596516649 719885386 846930886 1189641421 1649760492 1681692777 1714636915 1804289383 1957747793 Instead, I end up with: 1804289383 846930886 1681692777 1714636915 1957747793 424238335 719885386 1649760492 596516649 1189641421 Below is the code in question: //////////////////////////////////////////////// #include <iostream> #include <list> using namespace std; #include using namespace boost; //////////////////////////////////////////////// class my_class { public: int m_val; public: my_class(); bool operator<(const my_class&); void Display(); }; //////////////////////////////////////////////// my_class::my_class() { m_val = rand(); } bool my_class::operator<(const my_class& arg) { return m_val < arg.m_val; } void my_class::Display() { cout << m_val << "\n"; } //////////////////////////////////////////////// int main( int argc, char **argv ) { // list < my_class > my_list; // list < my_class >::iterator my_iter; list < shared_ptr < my_class > > my_list; list < shared_ptr < my_class > >::iterator my_iter; //populate my_list for (int x=0; x<10; x++) { // my_class tmp_obj; shared_ptr < my_class > tmp_obj; tmp_obj.reset(new my_class); my_list.push_back(tmp_obj); } //sort the list my_list.sort(); //display contents of my_list my_iter = my_list.begin(); while (my_iter != my_list.end()) { // (*my_iter).Display(); (*my_iter)->Display(); ++my_iter; } return 0; } //////////////////////////////////////////////// Thanks in advance for any help you may render...