How to Check any value in Array element is duplicate or not in C#

In this article, I will show you how to make a simple program to check any value is duplicate or not in Array. It will return true if the value exists duplicate in Array else false.

using System;
using System.Collections.Generic;

namespace testconsole

{
    class Program
    {
     static void Main(string[] args)
     {
             Console.WriteLine(checkduplicate(1,2,3,2,2));
            Console.ReadLine();
        }
        public static bool checkduplicate(params int[] A)
        {
            Dictionary<int, int> d = new Dictionary<int, int>();
            foreach (int i in A)
            {
                if (d.ContainsKey(i))
                    return true;
                else
                    d.Add(i, 1);
            }
            return false;
        }

    }

}