#include <iostream>
#include <string>

using namespace std;


string rev(string &s)
{
  string res;
  for (int i = s.size()-1; i >= 0; i--) { // unsigned not!
    res += s[i];
  }
  return res;
}

void rev_inplace(string &s)
{
  char temp;
  int j = s.size()-1;
  for (int i = 0; i < j; i++, j--) {
    temp = s[i];
    s[i] = s[j];
    s[j] = temp;
  }
}


int main()
{
  string s = "Asdf";
  cout << rev(s) << endl << "---" << endl;
  cout << s << endl;
  rev_inplace(s);
  cout << s << endl;
  return 0;
}