This program prompts you for the current date
and several birthdates.
It computes the age in years of the youngest
person and wishes Happy Birthday as appropriate.
Minimum allowed age? 21
Current year? 2009
Current month? 4
Current day? 28
Number of people? 3

Birth year? 1988
Birth month? 4
Birth day of month? 29

Birth year? 1986
Birth month? 4
Birth day of month? 28
Happy 23rd birthday!

Birth year? 1985
Birth month? 1
Birth day of month? 1

The youngest person is age 20
Sorry, you have not all reached your 21st birthday.