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 i, j, count, num;
 
        int[] arr = new int[100];
        int[] frequency = new int[100];
 
        //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());
            //Initially initialize frequency variable to -1
            frequency[i] = -1;
        }
 
 
        for (i = 0; i < num; i++)
        {
            count = 1;
            for (j = i + 1; j < num; j++)
            {
                //If duplicate element is found
                if (arr[i] == arr[j])
                {
                    count++;
 
                    //Make sure not to count frequency of same element again
                    frequency[j] = 0;
                }
            }
 
            //If frequency of current element is not counted
            if (frequency[i] != 0)
            {
                frequency[i] = count;
            }
        }
 
 
        //Print frequency of each element
        Console.WriteLine("\nFrequency of all elements of array : \n");
        for (i = 0; i < num; i++)
        {
            if (frequency[i] != 0)
            {
                Console.WriteLine(arr[i] + " occurs " + frequency[i]+ " times");                
            }
        }
 
 
        Console.ReadLine();
    }
 
}

Result