#include <string>
#include <list>
#include <algorithm>
#include <memory>
#include <iostream>
 
struct A
{
    std::string id ;
};
 
bool operator == ( const A& a, const std::string& str ) { return a.id == str ; }
bool operator < ( const A& first, const A& second ) { return first.id < second.id ; }
 
int main()
{
    std::list<A> seq { {"one"}, {"two"}, {"three"}, {"four"}, {"five"} } ;
 
    auto iter= std::find( std::begin(seq), std::end(seq), "three" ) ;
    A& alias = *iter ;
    A* ptr = std::addressof(alias) ;
 
    const auto dump = [&]
    {
        for( const auto& s : seq ) std::cout << s.id << ' ' ;
        std::cout << '\n' ;
        std::cout << iter->id << '/' << alias.id << '/' << ptr->id
                   << " at address " << ptr << "\n\n" ;
    };
 
    dump() ;
 
    seq.sort() ;
    dump() ;
 
    seq.insert( iter, { {"six"}, {"seven"}, {"eight"} } ) ;
    dump() ;
 
    seq.erase( std::find( std::begin(seq), std::end(seq), "four" ),
               std::find( std::begin(seq), std::end(seq), "seven" ) ) ;
    dump() ;
 
    seq.reverse() ;
    dump() ;
 
    // iterator/reference/pointer to A{"three"} have remained vaild till now
    // everything we have done upto here is a list operation
    // a list does not move its elements around in memory
 
    std::cout << "--------------------------\n" ;
 
    std::reverse(  std::begin(seq), std::end(seq) ) ;
    // iterator/reference/pointer to A{"three"} are now invalidated
    // iter no longer 'points' to A{"three"} etc.
    // the algorithm does move things around in memory
    dump() ;
}
 

I2luY2x1ZGUgPHN0cmluZz4KI2luY2x1ZGUgPGxpc3Q+CiNpbmNsdWRlIDxhbGdvcml0aG0+CiNpbmNsdWRlIDxtZW1vcnk+CiNpbmNsdWRlIDxpb3N0cmVhbT4KCnN0cnVjdCBBCnsKICAgIHN0ZDo6c3RyaW5nIGlkIDsKfTsKCmJvb2wgb3BlcmF0b3IgPT0gKCBjb25zdCBBJiBhLCBjb25zdCBzdGQ6OnN0cmluZyYgc3RyICkgeyByZXR1cm4gYS5pZCA9PSBzdHIgOyB9CmJvb2wgb3BlcmF0b3IgPCAoIGNvbnN0IEEmIGZpcnN0LCBjb25zdCBBJiBzZWNvbmQgKSB7IHJldHVybiBmaXJzdC5pZCA8IHNlY29uZC5pZCA7IH0KCmludCBtYWluKCkKewogICAgc3RkOjpsaXN0PEE+IHNlcSB7IHsib25lIn0sIHsidHdvIn0sIHsidGhyZWUifSwgeyJmb3VyIn0sIHsiZml2ZSJ9IH0gOwoKICAgIGF1dG8gaXRlcj0gc3RkOjpmaW5kKCBzdGQ6OmJlZ2luKHNlcSksIHN0ZDo6ZW5kKHNlcSksICJ0aHJlZSIgKSA7CiAgICBBJiBhbGlhcyA9ICppdGVyIDsKICAgIEEqIHB0ciA9IHN0ZDo6YWRkcmVzc29mKGFsaWFzKSA7CgogICAgY29uc3QgYXV0byBkdW1wID0gWyZdCiAgICB7CiAgICAgICAgZm9yKCBjb25zdCBhdXRvJiBzIDogc2VxICkgc3RkOjpjb3V0IDw8IHMuaWQgPDwgJyAnIDsKICAgICAgICBzdGQ6OmNvdXQgPDwgJ1xuJyA7CiAgICAgICAgc3RkOjpjb3V0IDw8IGl0ZXItPmlkIDw8ICcvJyA8PCBhbGlhcy5pZCA8PCAnLycgPDwgcHRyLT5pZAogICAgICAgICAgICAgICAgICAgPDwgIiBhdCBhZGRyZXNzICIgPDwgcHRyIDw8ICJcblxuIiA7CiAgICB9OwoKICAgIGR1bXAoKSA7CgogICAgc2VxLnNvcnQoKSA7CiAgICBkdW1wKCkgOwoKICAgIHNlcS5pbnNlcnQoIGl0ZXIsIHsgeyJzaXgifSwgeyJzZXZlbiJ9LCB7ImVpZ2h0In0gfSApIDsKICAgIGR1bXAoKSA7CgogICAgc2VxLmVyYXNlKCBzdGQ6OmZpbmQoIHN0ZDo6YmVnaW4oc2VxKSwgc3RkOjplbmQoc2VxKSwgImZvdXIiICksCiAgICAgICAgICAgICAgIHN0ZDo6ZmluZCggc3RkOjpiZWdpbihzZXEpLCBzdGQ6OmVuZChzZXEpLCAic2V2ZW4iICkgKSA7CiAgICBkdW1wKCkgOwoKICAgIHNlcS5yZXZlcnNlKCkgOwogICAgZHVtcCgpIDsKCiAgICAvLyBpdGVyYXRvci9yZWZlcmVuY2UvcG9pbnRlciB0byBBeyJ0aHJlZSJ9IGhhdmUgcmVtYWluZWQgdmFpbGQgdGlsbCBub3cKICAgIC8vIGV2ZXJ5dGhpbmcgd2UgaGF2ZSBkb25lIHVwdG8gaGVyZSBpcyBhIGxpc3Qgb3BlcmF0aW9uCiAgICAvLyBhIGxpc3QgZG9lcyBub3QgbW92ZSBpdHMgZWxlbWVudHMgYXJvdW5kIGluIG1lbW9yeQoKICAgIHN0ZDo6Y291dCA8PCAiLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS1cbiIgOwoKICAgIHN0ZDo6cmV2ZXJzZSggIHN0ZDo6YmVnaW4oc2VxKSwgc3RkOjplbmQoc2VxKSApIDsKICAgIC8vIGl0ZXJhdG9yL3JlZmVyZW5jZS9wb2ludGVyIHRvIEF7InRocmVlIn0gYXJlIG5vdyBpbnZhbGlkYXRlZAogICAgLy8gaXRlciBubyBsb25nZXIgJ3BvaW50cycgdG8gQXsidGhyZWUifSBldGMuCiAgICAvLyB0aGUgYWxnb3JpdGhtIGRvZXMgbW92ZSB0aGluZ3MgYXJvdW5kIGluIG1lbW9yeQogICAgZHVtcCgpIDsKfQo=