#include <iostream>

#include <string>

#include <memory>

using namespace std;

const char* string2constchar(string s){

    shared_ptr<string> tmp (new string(s));

    return tmp->c_str();

}

int main()

{

    string s = "demo";

    char *_c = new char[s.size() + 1];

    copy(s.begin(), s.end(), _c);

    _c[s.size()] = '\0';

    const char* c = string2constchar(s);

    std::cout << c << std::endl;

    std::cout << _c << std::endl;

    s = "test";

    std::cout << c << std::endl;

    std::cout << _c << std::endl;

    delete _c;

    return 0;

}