std::basic_string<CharT,Traits,Allocator>::rend, std::basic_string<CharT,Traits,Allocator>::crend

#include <algorithm>
#include <iostream>
#include <iterator>
#include <string>

int main()
{
    std::string p("[A man, a plan, a canal: Panama]");
    std::string q;
    
    std::copy(p.crbegin(), p.crend(), std::back_inserter(q));
    std::cout << "q = " << q << '\n';
    
    std::copy(q.crbegin(), q.crend(), p.rbegin());
    std::cout << "p = " << p << '\n';
}