public void IsTriangular_ValueValue_ReturnsTrueOrFalse(int testNumber, bool expectedResult)
{
bool result = TriangularNumbers.IsTriangular(testNumber);
Assert.That(result, Is.EqualTo(expectedResult));
}
public void GetNthTriangular_ValidValue_ReturnsTriangularNumber(int triangleToGet, int expectedResult)
{
int result = TriangularNumbers.GetNthTriangular(triangleToGet);
Assert.That(result, Is.EqualTo(expectedResult));
}
public void GetCLosestTriangular_ValidValue_ReturnsClosestTriangular(int baseNumber, int expectedResult)
{
int result = TriangularNumbers.GetClosestTriangular(baseNumber);
Assert.That(result, Is.EqualTo(expectedResult));
}
static void Main(string[] args)
{
/*
* The sequence of triangle numbers is generated by adding the natural numbers.
* So the 7th triangle number would be 1 + 2 + 3 + 4 + 5 + 6 + 7 = 28.
*
* The first ten terms would be:
* 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
*
* Let us list the factors of the first seven triangle numbers:
*
* 1: 1
* 3: 1,3
* 6: 1,2,3,6
* 10: 1,2,5,10
* 15: 1,3,5,15
* 21: 1,3,7,21
* 28: 1,2,4,7,14,28
* We can see that 28 is the first triangle number to have over five divisors.
*
* What is the value of the first triangle number to have over five hundred divisors?
* Answer: 76576500
*/
Stopwatch timer = new Stopwatch();
Console.WriteLine("Find the first Triangular Number with at least the specified number of divisors.");
Console.WriteLine("--------------------------------------------------------------------------------");
Console.WriteLine();
Console.Write("How many divisors do you want? ");
int divisorsWanted = int.Parse(Console.ReadLine());
int triangularNumber = 3;
int triangularNumberValue = 0;
bool hasRequiredDivisors = false;
int mostDivisors = 0;
timer.Start();
while (!hasRequiredDivisors)
{
triangularNumber++;
triangularNumberValue = TriangularNumbers.GetNthTriangular(triangularNumber);
int divisors = Factors.GetAllFactors(triangularNumberValue).Length;
if (divisors > mostDivisors)
{
mostDivisors = divisors;
}
if (divisors >= divisorsWanted)
{
hasRequiredDivisors = true;
}
}
timer.Stop();
Console.WriteLine("The first Triangular Number with {0} divisors is ({1}) {2}",
divisorsWanted, triangularNumber, triangularNumberValue);
Console.WriteLine(timer.Elapsed);
Console.ReadLine();
}
