Use std::reverse_iterator
:
#include <iostream>
#include <iterator>
int main() {
const char* s = "abc";
std::reverse_iterator<const char*> first(s + 3);
std::reverse_iterator<const char*> last(s);
for( ; first != last; ++first) {
std::cout << *first;
}
std::cout << '\n';
return 0;
}