/*

Given an array of numbers. Print all the pairs (2) of numbers in the array if the sum of those numbers is also present in the array. 

​

Input

int a[] = {10, 5, 2, 7, 7, 49}

Output  (5,2)

*/

​

using System;

public class Program

{

    public static void Main()

    {

        int[] a = new int[]{10, 5, 2, 7, 7, 49, 12};

        for(int i=0;i<a.Length-1;i++)

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

            {

                int s=a[i]+a[j];

                if(Array.FindIndex(a,0, p=>p==s)>=0)

                    Console.WriteLine("{0}, {1}",a[i],a[j]);

            }

    }

}