#include <iostream>
#include <string>

using namespace std;

int main () {
    string greeting {"Hello World!"};
    int i;

    cout << greeting << " is " << greeting.length() 
         << " characters long" << endl;

    i = 0;

    while ( i < greeting.size() ) {
       //cout << greeting[i] << endl;
       cout << greeting.at(i) ;
       ++i;
    }

    cout << endl;
    cout << endl;
  
    i = greeting.size() -1;
    while ( i >= 0) {
       cout << greeting.at(i) ;
       --i;
    }
    cout << endl;
    cout << endl;

    i = 0;
    while ( i < greeting.size() ) {
       greeting.at(i) = toupper(greeting.at(i));
       ++i;
    }
    cout << greeting << endl;

    return 0;
}