#include <iostream>

#include <string>

using namespace std;

​

int main() {

  string myString = "Hello";

  cout << "Original string: " << myString << "\n";

  cout << "First character: " << myString.at(0) << "\n";

  cout << "Second character: " << myString.at(1) << "\n";

  cout << "Last character: " << myString.at(myString.length() - 1) << "\n";

  myString.at(0) = 'J';

  cout << "Changed string: " << myString;

  return 0;

}

​