public static void Sample_Repunit_Factors()
{
//this example shows how to use repunit to solve problem
//Determining sum of the first forty prime factors of a repunit length of 10^9
//(Question from http://projecteuler.net)
var repunit = new Repunit(10L.Power(9));
Console.WriteLine(new Prime().TakeWhile(p => true).Where(repunit.IsDivisibleBy).Take(40).Sum());
}
public static void Length()
{
//this example shows how to get repunit length
//create Repunit by Repunit.CreateDivisibleBy(num)
var repunit = Repunit.CreateDivisibleBy(7);
//use repunit.Length to get length
Console.WriteLine("{0} has length of {1}", repunit, repunit.Length);
}
public static void CreateDivisibleBy()
{
//this example shows how to create least value repunit which is divisible by a number
//create Repunit by Repunit.CreateDivisibleBy(num)
var repunit = Repunit.CreateDivisibleBy(7);
//show result
Console.WriteLine("{0}/7 = {1}", repunit, int.Parse(repunit.ToString()) / 7);
}
public static void Create()
{
//this example shows how to create Repunit
//create Repunit by new Repunit(length)
var repunit = new Repunit(4);
//show result
Console.WriteLine(repunit);
}
public static void IsDivisibleBy()
{
//this example shows if the repunit is divisible by a number
//create Repunit
var repunit = new Repunit(10);
//use repunit.IsDivisibleBy(num) to get if the repunit is divisibly by a number
Console.WriteLine("Is {0} divisible by 441? {1}", repunit, repunit.IsDivisibleBy(441));
Console.WriteLine("Is {0} divisible by 451? {1}", repunit, repunit.IsDivisibleBy(451));
}
