In C#, how do I calculate someone's age based on a DateTime type birthday?

Question

Given a DateTime representing a person\'s birthday, how do I calculate their age in years?

Answer 1

SQL version:

declare @dd smalldatetime = '1980-04-01'
declare @age int = YEAR(GETDATE())-YEAR(@dd)
if (@dd> DATEADD(YYYY, -@age, GETDATE())) set @age = @age -1

print @age