overlap in memcpy

#include <boost/regex.hpp>
#include <string>
#include <iostream>

using namespace std;
using namespace boost;

int main(int argc, char *argv[]) {
        if (argc < 2)
                return -1;

        string url = argv[1];

        cout << "url: " << url << endl;

        /* first problem */
        regex rx("((https?)\\://)?([^\\:/]+)(:([0-9]+))?(/[^\\?#]*)?(\\?([^#]*))?(#(.*))?");
        smatch match;

        if (regex_match(url, match, rx)) {
                cout << "scheme: " << match[2] << endl;
                cout << "domain: " << match[3] << endl;
                if (!match[5].str().empty())
                        cout << "port: " << match[5] << endl;
                if (!match[6].str().empty())
                        cout << "path: " << match[6] << endl;
                if (!match[8].str().empty())
                        cout << "query: " << match[8] << endl;
                if (!match[10].str().empty())
                        cout << "id: " << match[10] << endl;
        } else {
                cout << "!regex_match()" << endl;
        }


        /* second problem */
        string toRemove = "http://";
        size_t found = 0;
        if ((found = url.find(toRemove)) != string::npos) {
                cout << "found: " << found << endl;
                url.erase(found, toRemove.size());
        }


        return 0;
}