CumulativeStarsToLevel -> AccountLevel

//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            //Your code goes here
            Console.WriteLine("Hello, world!");
            int a, b, c;
            for(int i = 0; i < 50; i++)
            {
                GetLevelFromStars(i, out a, out b, out c);
            }
        }
        static List<int> cumulativeStarsAtLevel = new List<int>{6, 15, 27, 42, 60};
        public static void GetLevelFromStars(int myStars, out int myLevel, out int starsToNextLevel, out int myProgressToNextLevel)
        {
            int lvlIndex = cumulativeStarsAtLevel.BinarySearch(myStars);
            lvlIndex = lvlIndex < 0 ? ~lvlIndex : lvlIndex+1;
            starsToNextLevel = myProgressToNextLevel = 0;

            myLevel = lvlIndex+1;

            int cumulativeStarsToCurrentLevel = lvlIndex > 0 ? cumulativeStarsAtLevel[lvlIndex-1] : 0;
            int cumulativeStarsToNextLevel = lvlIndex < cumulativeStarsAtLevel.Count() ? cumulativeStarsAtLevel[lvlIndex] : myStars;

            starsToNextLevel = cumulativeStarsToNextLevel - myStars;
            myProgressToNextLevel = myStars - cumulativeStarsToCurrentLevel;


            Console.WriteLine(String.Format("@{0},\tlvl{1},\t({2} / {3})", myStars, myLevel, myProgressToNextLevel, myProgressToNextLevel + starsToNextLevel));

        }
    }
}