After:

void printDate( int year, int month, int day )
{
   cout << month << "-" << day << "-" << year << endl;
}

void inputDate( int & year, int & month, int & day )
{
   year = inputYear();
   month = inputMonth();
   day = inputDay( year, month );
}

int inputDay( int year, int month )
{
   int day;
   int maxDays = computeDaysInMonth( year, month );
 
   do
   {
      cout << "Enter the day" << endl;
      cin >> day;
   } while( !( day >= 1 && day <= maxDays ) ); 

   return day;
}