c++ how to remove filename from path string

The easiest way is to use find_last_of member function of std::string

string s1("../somepath/somemorepath/somefile.ext");
string s2("..\\somepath\\somemorepath\\somefile.ext");
cout << s1.substr(0, s1.find_last_of("\\/")) << endl;
cout << s2.substr(0, s2.find_last_of("\\/")) << endl;

This solution works with both forward and back slashes.