using System;

public class Program

{

    public static void Main()

    {

        int[] skills = new int[4];

​

        int pointsToDistribute = 10;

        var rnd = new Random ();

        for (int i = 0; i < pointsToDistribute; i++)

        {

            int whichSkill = rnd.Next (0, 4);

            skills[whichSkill]++;

        }

        skills.Dump (); // .NET Fiddle

    }

}

​