The illustration shows a code segment with an annotation “This is an improved version of the class DayOfYear that we gave in Display 10.3.” The lines are numbered from 1 through 41 and the annotations are as follows:

"//Program to demonstrate the class DayOfYear.
#include <iostream>
using namespace std;
class DayOfYear
{
public:
void input( );
void output( );
void set(int newMonth, int newDay);
//Precondition: newMonth and newDay form a possible date.
//Postcondition: The date is reset according to the arguments.
int getMonth( );
//Returns the month, 1 for January, 2 for February, etc.
int getDay( );
//Returns the day of the month.
private:"
"void checkDate( );" annotated as "Private member function."
"int month;
int day;" annotated as "Private member variable."
"};
int main( )
{
DayOfYear today, bachBirthday;
cout << "Enter today's date:\n";
today.input( );
cout << "Today's date is ";
today.output( );
bachBirthday.set(3, 21);
cout << "J. S. Bach's birthday is ";
bachBirthday.output( );
if (today.getMonth( ) == bachBirthday.getMonth( ) &&
today.getDay( ) == bachBirthday.getDay( ) )
out << "Happy Birthday Johann Sebastian!\n";
else
cout << "Happy Unbirthday Johann Sebastian!\n";
return 0;
}
 //Uses iostream:
void DayOfYear::input( )
{
cout << "Enter the month as a number: ";"