Introduction

I have used Visual Studio 2012 for debugging purpose. But you can use any version of visul studio as per your availability.

using System;
class Program
{
    static void Main()
    {       
        int[] arr = new int[100];
        int num; // Total number of elements in array
        int i, j, k;
 
        //Reads size of the array
        Console.WriteLine("Enter size of the array: ");
        num = Convert.ToInt32(Console.ReadLine());
 
        //Reads elements in array
        Console.WriteLine("Enter elements in the array: ");
        for (i = 0; i < num; i++)
        {
            arr[i] = Convert.ToInt32(Console.ReadLine());           
        }
 
 
        // Finding all duplicate elements in array
 
        for (i = 0; i < num; i++)
        {
            for (j = i + 1; j < num; j++)
            {
                //If any duplicate found */
                if (arr[i] == arr[j])
                {
                    // Delete the current duplicate element
                    for (k = j; k < num; k++)
                    {
                        arr[k] = arr[k + 1];
                    }
 
                    //Decrement size after removing duplicate element
                    num--;
 
                    // If shifting of elements occur then don't increment j
                    j--;
                }
            }
        }
 
        // Print array after deleting duplicate elements
        Console.WriteLine("\nArray elements after deleting duplicates : ");
        for (i = 0; i < num; i++)
        {
            Console.WriteLine(arr[i]);
        }        
 
        Console.ReadLine();
    }
 
}

Result