C#

public struct Diff
{
  public int Years;
  public int Months;
  public int Days;
};

//Will return incorrect negative values if end < start
public Diff Difference(DateTime start, DateTime end)
{
  Diff diff = new Diff();

  //Not as far into month, so it doesn't count
  if (end.Day < start.Day)
  {
    end = end.AddMonths(-1);

    //Calc diff
    int remainDays = DateTime.DaysInMonth(start.Year, start.Month) - start.Day;
    diff.Days = remainDays + end.Day;
  }
  else
    diff.Days = end.Day - start.Day;

  //Not as far into year, so it doesn't count
  if (end.Month < start.Month)
  { 
    end = end.AddYears(-1);
  
    //Calc diff
    diff.Months = 12 - (start.Month - end.Month);
  }
  else
    diff.Months = end.Month - start.Month;

  diff.Years = end.Year - start.Year;

  return diff;
}

stephen.darling wrote:

)What is the best (as in most random) way of generating a number between 0 and
36?

PIEBALDconsult wrote:

With a roulette wheel.

PIEBALDconsult wrote:

As to the horse, he may be favored to win, but he doesn't have an "80% chance of winning". However, one of the techniques I like to use to select a random entity, from amomg various entities with varying chances of being selected, is to simulate putting slips into a hat, each entity may have a different number of slips in the hat, in proportion to their desired probability to be drawn.

stephen.darling wrote:

Please could you explain this a little further?

static Random _r = new Random();
static int F()
{
    int n = _r.Next(0,36);
    return n;
}

static void Main()
    {
        //if you want card with 6 numbers

            int[] numbers = new int[6];


        //to put different numbers at each place on the array


            for (int i = 0; i < numbers.Length; i++)
            {
                int a = F();
                bool has = numbers.Contains(a);
                if (has == true) {i--; }
                else {
                    numbers[i]=a;
                }
            }


        //to sort it and print it

            Array.Sort(numbers);

            int j = 0;
            foreach (int i in numbers)
            {
                Console.WriteLine("number at place " + (j+1).ToString() +" is " +i.ToString());
                j++;
            }
            Console.ReadLine();


    }

            static Random _r = new Random();
            static int F()
            {
                int n = _r.Next(0,36);
                return n;
            }

static void Main(string[] args)
{
    int a = F();

    //if random number wich is between 1 and 100 is smaler or equal 80 than horse win
    if (a <= 80)
    {
        Console.Write("horse win!");
    }
    //else horse lose
    else { Console.Write("horse lose!"); }
    //and to check what is current value of number a - wich is number between 1 and 100
    Console.Write(" value of a is " + a.ToString());
    Console.ReadLine();
}
static Random _r = new Random();
static int F()
{
    int n = _r.Next(1, 100);
    return n;
}

public int RunAndReturnFinalAngle(int startRadius, int wheelRadius)
        {
            Random rng = new Random();
            int sampleCount = 360;
            int currentStep = 1;
            int delayTime = rng.Next(10, 100);
            int currentRadius = startRadius;
            int radiusReduction = rng.Next(1, 5);

            double ballX = 0;
            double ballY = 0;

            int angle = 0;

            while (currentRadius > wheelRadius)
            {
                currentStep++;
                if(currentStep > sampleCount){currentStep = 1;}
                
                //angle of ball from vertical
                angle = 360 * (currentStep / sampleCount);

                //coordinates of ball on circular trajectory
                ballX = currentRadius * Math.Sin(angle);
                ballY = currentRadius * Math.Cos(angle);

                PositionBallGraphic(ballX, ballY);

                //reduce trajectory radius by random ammount - Randomness element 1
                currentRadius -= radiusReduction;
                
                //Sleep random time to give ball a random speed - Randomness element 2
                Thread.Sleep(delayTime);
            }

            return angle;
        }

public int GetNumberIndexForBall(int ballAngle, int wheelAngle)
        {
            int angleRelativeToWheel = ballAngle - wheelAngle;

            //assume 36 numbers on wheel
            return angleRelativeToWheel / 10;

        }

stephen.darling wrote:

I now realise that I need to sit down with a good book.

stephen.darling wrote:

I have just purchased "Head First C#" 2nd edition.

stephen.darling wrote:

if I have made a good choice for a first book

Bastard Programmer from Hell

Eddy Vluggen wrote:

Good decision

Eddy Vluggen wrote:

That's being used in school 'ere; covers a lot, reads quite pleasantly.

Eddy Vluggen wrote:

Yup, definitely worth the time