/*
 *  C# Program to Perform Merge Sort
 */
using System;
using System.Collections.Generic;
using System.Text;
namespace prog
{
class Program
{
    static public void mergemethod(int [] numbers, int left, int mid, int right)
    {
        int [] temp = new int[25];
        int i, left_end, num_elements, tmp_pos;
        left_end = (mid - 1);
        tmp_pos = left;
        num_elements = (right - left + 1);
        while ((left <= left_end) && (mid <= right))
            {
                if (numbers[left] <= numbers[mid])
                    temp[tmp_pos++] = numbers[left++];
                else
                    temp[tmp_pos++] = numbers[mid++];
            }
        while (left <= left_end)
            temp[tmp_pos++] = numbers[left++];
        while (mid <= right)
            temp[tmp_pos++] = numbers[mid++];
        for (i = 0; i < num_elements; i++)
            {
                numbers[right] = temp[right];
                right--;
            }
    }
    static public void sortmethod(int [] numbers, int left, int right)
    {
        int mid;
        if (right > left)
            {
                mid = (right + left) / 2;
                sortmethod(numbers, left, mid);
                sortmethod(numbers, (mid + 1), right);
                mergemethod(numbers, left, (mid+1), right);
            }
    }
    static void Main(string[] args)

    {
        int[] numbers = { 3, 8, 7, 5, 2, 1, 9, 6, 4 };
        int len = 9;
        Console.WriteLine("MergeSort :");
        sortmethod(numbers, 0, len - 1);
        for (int i = 0; i < 9; i++)
            Console.WriteLine(numbers[i]);
        Console.Read();
    }
}
}

/*
MergeSort :
1
2
3
4
5
6
7
8
9