I know I missed the boat on getting the accepted answer, but after giving Kirk Broadhurst a lashing I thought I better provide my own answer.
My reading of the question was that chamara wanted something like this:
var birthDate = new DateTime(1923, 4, 20);
var starSign = StarSigns.GetFor(birthDate);
Console.WriteLine(starSign); // Taurus (April 20 - May 20)
Console.WriteLine(starSign.GetStartDate(2010)); // 2010/04/20 00:00:00
Console.WriteLine(starSign.GetEndDate(2010)); // 2010/05/20 23:59:59
var starSign1 = StarSigns.GetFor(10, 22);
var starSign2 = StarSigns.GetFor(10, 23);
Console.WriteLine(starSign1); // Libra (September 23 - October 22)
Console.WriteLine(starSign2); // Scorpio (October 23 - November 21)
So here are my classes:
public static class StarSigns
{
private static StarSign[] _starSigns;
static StarSigns()
{
var names = new[]
{
"Aquarius", "Pisces", "Aries", "Taurus",
"Gemini", "Cancer", "Leo", "Virgo",
"Libra", "Scorpio", "Sagittarius", "Capricorn",
};
var days = new[]
{
20, 18, 20, 20,
21, 21, 22, 23,
23, 23, 22, 22,
};
_starSigns = (from i in Enumerable.Range(0, 12)
let name = names[i]
let startMonth = i + 1
let startDay = days[i]
let endDay = days[(i + 1) % 12] - 1
select new StarSign(name, startMonth, startDay, endDay)).ToArray();
}
public static StarSign GetFor(DateTime birthDate)
{
return (from starSign in _starSigns
let startDate = starSign.GetStartDate(birthDate.Year)
let endDate = starSign.GetEndDate(birthDate.Year)
where startDate <= birthDate
where endDate >= birthDate
select starSign).Single();
}
public static StarSign GetFor(int birthMonth, int birthDay)
{
return GetFor(new DateTime(2010, birthMonth, birthDay));
}
}
public class StarSign
{
public StarSign(string name, int startMonth, int startDay, int endDay)
{
this.Name = name;
this.StartMonth = startMonth;
this.StartDay = startDay;
this.EndDay = endDay;
}
public string Name { get; private set; }
public int StartDay { get; private set; }
public int EndDay { get; private set; }
public int StartMonth { get; private set; }
public int EndMonth
{
get
{
return this.StartMonth + 1;
}
}
public DateTime GetStartDate(int year)
{
return new DateTime(year, this.StartMonth, this.StartDay);
}
public DateTime GetEndDate(int year)
{
var nextStart = new DateTime(year, (this.StartMonth % 12) + 1, this.EndDay + 1);
return nextStart.Subtract(TimeSpan.FromTicks(1));
}
public string Period
{
get
{
var startDate = this.GetStartDate(2010);
var endDate = this.GetEndDate(2010);
var template = "{0:MMMM dd} - {1:MMMM dd}";
return String.Format(template, startDate, endDate);
}
}
public override string ToString()
{
return String.Format("{0} ({1})", this.Name, this.Period);
}
}
Enjoy!