c#编程：随机输入21个整数，将它们按从小到大顺序排列输出，并求出中间三个数之和

using System;
using System.Linq;

public class Test
{
    public static void Main()
    {
        // your code goes here
        int[] arr = new int[21];
        Random rnd = new Random();
        for (int i = 0; i < 21; i++)
            arr[i] = rnd.Next(0, 100);
arr = arr.OrderBy(x => x).ToArray();
        Console.WriteLine("{0}", arr[9] + arr[10] + arr[11] );
    }
}

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