Simple random class with one time occurring random numbers!

I made a simple random class so that each number occurs one time. This way, you can get a random number without fear of one number occurring more than once. If you wish to do so, you can make the classes static too.

Code:

class MyOwnRandom
    {
        
        List<int> alreadyCalledNumbers = new List<int>();
        
        Random random = new Random();

        public int next(int min, int max)
        {
            int randomNumber;
            randomNumber = random.Next(min,max);
            
            while(alreadyCalledNumbers.Contains(randomNumber))
            {
                randomNumber = random.Next(min, max);
            }

            alreadyCalledNumbers.Add(randomNumber);
            return randomNumber;
        }
        public int next(int max)
        {
            int randomNumber;
            randomNumber = random.Next(max);

            while (alreadyCalledNumbers.Contains(randomNumber))
            {
                randomNumber = random.Next(max);
            }

            alreadyCalledNumbers.Add(randomNumber);
            return randomNumber;
        }
        public void reset()
        {
            alreadyCalledNumbers.Clear();
        }
    }

Originally Posted by Laslod

Code:

class MyOwnRandom
    {
        
        List<int> alreadyCalledNumbers = new List<int>();
        
        Random random = new Random();

        public int next(int min, int max)
        {
            int randomNumber;
            randomNumber = random.Next(min,max);
            
            while(alreadyCalledNumbers.Contains(randomNumber))
            {
                randomNumber = random.Next(min, max);
            }

            alreadyCalledNumbers.Add(randomNumber);
            return randomNumber;
        }
        public int next(int max)
        {
            int randomNumber;
            randomNumber = random.Next(max);

            while (alreadyCalledNumbers.Contains(randomNumber))
            {
                randomNumber = random.Next(max);
            }

            alreadyCalledNumbers.Add(randomNumber);
            return randomNumber;
        }
        public void reset()
        {
            alreadyCalledNumbers.Clear();
        }
    }

Would hit infinite looping really easily.

Code:

var rnd = new MyOwnRandom();
for(int i = 0; i < 10; ++i)
    Console.WriteLine(rnd.next(1,5));

Would never work. I'm not quite sure when you'd need something like this to be quite honest.

Originally Posted by Jason

Would hit infinite looping really easily.

Code:

var rnd = new MyOwnRandom();
for(int i = 0; i < 10; ++i)
    Console.WriteLine(rnd.next(1,5));

Would never work. I'm not quite sure when you'd need something like this to be quite honest.

When you want a random number but don't want it to appear more than once. Let's say you have an enum with names, and you want to get a random amount of names from that enum. You wouldn't want a name to appear twice, so you can use something like this to get a random name and make sure that name doesn't come up again.

Originally Posted by Laslod

If you were using an enum to store names...that's a rather weird way of doing. Also, you could just iterate over an array to get distinct values, shuffling the array if necessary. For example:

Code:

public class RandomizedCollection<TInput>
    {
        // Random provider
        [ThreadStatic]
        private static Random _random;
        private static Random Random { get { return _random ?? (_random = new Random(System.Threading.Interlocked.Increment(ref _seed))); } }
        private static int _seed = Environment.TickCount;

        // Allow for progressive stepping through the collection, with lazy evaluation
        private readonly IEnumerator<TInput> _enumerator;
        private bool _hasNext;

        public bool HasNext { get { return _hasNext; } }

        public RandomizedCollection(IEnumerable<TInput> original)
        {
            _enumerator = original.OrderBy(t => Random.Next()).GetEnumerator();
            _hasNext = _enumerator.MoveNext(); // move to the beginning of the collection
        }

        public TInput Next()
        {
            if (!_hasNext)
                throw new InvalidOperationException("Reached the end of the collection");

            var value = _enumerator.Current;
            _hasNext = _enumerator.MoveNext();
            return value;
        }
    };

Would be a fairly trivial way of getting each value of a collection ONCE-ONLY, in a random order.

For example:

Code:

var stuff = new[] {
                "hello",
                "world",
                "this",
                "is",
                "a",
                "random",
                "string",
                "array"
            };

            var randomized = new RandomizedCollection<string>(stuff);
            while(randomized.HasNext())
                Console.WriteLine(randomized.Next());
            Console.Read();

Of course, this is really unnecessary encapsulation, as it's essential just a wrapper around something like:

Code:

var rnd = new Random(Environment.TickCount);
foreach(var item in stuff.OrderBy(s => rnd.Next()))
    Console.WriteLine(item);

But you get the idea.

Originally Posted by Jason

If you were using an enum to store names...that's a rather weird way of doing. Also, you could just iterate over an array to get distinct values, shuffling the array if necessary.

But you get the idea.

Oh yea I know I can use arrays but this way I don't have to. I can reuse it the class whenever I want and can use it for lots of other things but I get your idea.

Simple random class with one time occurring random numbers!

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