Second max element in a array

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace SecMax
{
class Program
{
static void Main(string[] args)
{
int[] arr = { 10000, 2000, 300, 200, 1, 50, 56, 72 };


//assumption: no 2 numbers will be equal. That part is not covered

if (arr[0] < arr[1])
{
int temp = arr[0];
arr[0] = arr[1];
arr[1] = temp;
}

for (int i = 2; i <= arr.Length - 1; i++)
{
if (arr[i] >= arr[0])
{
arr[0] = arr[i];
}
else if (arr[i] >= arr[1])
{
arr[1] = arr[i];
}
}

Console.WriteLine(arr[0]);
Console.WriteLine(arr[1]);

Console.ReadLine();
}
}
}