```
using System;
using System.Numerics;
using System.Diagnostics;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
class Problem
{
    // Check if in given list of numbers, are any two numbers closer to each other than
    // given threshold.
    // >>> HasCloseElements((new List<float>(new float[]{(float)1.0f, (float)2.0f, (float)3.0f})), (0.5f))
    // (false)
    // >>> HasCloseElements((new List<float>(new float[]{(float)1.0f, (float)2.8f, (float)3.0f, (float)4.0f, (float)5.0f, (float)2.0f})), (0.3f))
    // (true)
    public static bool HasCloseElements(List<float> numbers, float threshold)
    {

        numbers.Sort();
        for (int i = 0; i < numbers.Count - 1; i++)
        {
            if (Math.Abs(numbers[i] - numbers[i + 1]) < threshold)
            {
                return true;
            }
        }
        return false;

    }


    public static void Main(string[] args)
    {
        Debug.Assert(HasCloseElements((new List<float>(new float[] { (float)1.0f, (float)2.0f, (float)3.9f, (float)4.0f, (float)5.0f, (float)2.2f })), (0.3f)) == (true));
        Debug.Assert(HasCloseElements((new List<float>(new float[] { (float)1.0f, (float)2.0f, (float)3.9f, (float)4.0f, (float)5.0f, (float)2.2f })), (0.05f)) == (false));
        Debug.Assert(HasCloseElements((new List<float>(new float[] { (float)1.0f, (float)2.0f, (float)5.9f, (float)4.0f, (float)5.0f })), (0.95f)) == (true));
        Debug.Assert(HasCloseElements((new List<float>(new float[] { (float)1.0f, (float)2.0f, (float)5.9f, (float)4.0f, (float)5.0f })), (0.8f)) == (false));
        Debug.Assert(HasCloseElements((new List<float>(new float[] { (float)1.0f, (float)2.0f, (float)3.0f, (float)4.0f, (float)5.0f, (float)2.0f })), (0.1f)) == (true));
        Debug.Assert(HasCloseElements((new List<float>(new float[] { (float)1.1f, (float)2.2f, (float)3.1f, (float)4.1f, (float)5.1f })), (1.0f)) == (true));
        Debug.Assert(HasCloseElements((new List<float>(new float[] { (float)1.1f, (float)2.2f, (float)3.1f, (float)4.1f, (float)5.1f })), (0.5f)) == (false));
    }

}
```