Avoiding un-necessary shared_ptr copy when iterating over a container. Paste code into http://www.compileonline.com/compile_cpp11_online.php for testing.

shared_ptr iteration.cpp

#include <iostream>
#include <string>
#include <vector>
#include <memory>

using namespace std;

int main()
{
    vector<shared_ptr<string>> strings;
    strings.push_back(make_shared<string>("foo"));
    strings.push_back(make_shared<string>("bar"));
    
    for (auto &s : strings)
    {
        cout << s.use_count() << endl;
    }

   return 0;
}