using System.Collections.Generic;

using System;

​

public class Program

{

    public static void Main()

    {

        int[] array={2,9,6,3,1,4,}; //1,5,7,8,3,5};     

        Dictionary<int,int> map=new Dictionary<int,int>();

        int sum=10;

        for(int i=0;i<array.Length;i++)

        {

            int diff=sum-array[i];

            if(map.ContainsValue(diff))

            {

                Console.WriteLine(" "+array[i]+" -- "+diff);

            }

            map.Add(i, array[i]);

        }

                        Console.WriteLine(" using Array");

bool flag= false;

        for(int i=0;i< array.Length;i++)

        {

            for(int j=i+1;j< array.Length;j++)

            {

                if(array[i]+array[j] == sum)

                {

                    Console.WriteLine(" "+array[i]+" -- "+array[j]);

                    flag = true;

​

                }

            }

        }   

            if(flag==false)

                Console.WriteLine("not found");

​

    }

}