#include <iostream>
#include <string>
#include <ctype.h>

using namespace std;

class mystring : public string
{
public:
  void toupper();

};

void mystring::toupper()
{
  for (int i=0; i<length(); i++) {
    at(i) = ::toupper(at(i));
  }

};


int main()
{
  mystring greeting;
  greeting.assign("Hello, World!");
  
  cout << greeting << endl;
  greeting.toupper();
  cout << greeting << endl;
  

}