随机生成，并求平均数

随机生成10个小于100的整数，并放入一维数组中存放，编程求其中小于80且大于9的书的平均数，保留两位小数

#include <stdio.h>
#include <iostream>
#include <time.h>

int main()
{
    srand((unsigned)time(NULL));
    int num[10] = { 0 }, sum = 0,count=0;
    for (int i = 0; i < 10; i++)
    {
        num[i] = rand() % 100;
        if (num[i] > 9 && num[i] < 80) {
            sum += num[i];
            printf("%d ", num[i]);
            count += 1;
        }
    }
    printf("\n平均数为：%.2f\n", 1.0 * sum / count);
    system("pause");
    return 0;
}

代码如下：

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

namespace random
{
    class Program
    {
        static void Main(string[] args)
        {
            Random r = new Random();
            
            int[] a = new int[10];
            Console.WriteLine("随机产生的原数组：");
            for(int i=0;i<a.Length;i++)
            {
                a[i] = r.Next(1, 100);
                Console.Write(a[i] + " ");
            }
            Console.WriteLine();
            //升序
            Array.Sort(a);
            Console.WriteLine("升序后的数组：");
            for(int j=0;j<a.Length;j++)
            {
                Console.Write(a[j] + " ");
            }
            Console.WriteLine();
            //反转（将升序反转过后就是降序）
            Array.Reverse(a);
            Console.WriteLine("（反转）降序后的数组：");
            for (int n = 0; n < a.Length; n++)
            {
                Console.Write(a[n] + " ");
            }
            Console.ReadKey();

        }
    }
}

Random rand = new Random(DateTime.Now.Millisecond);
var result = Enumerable.Range(1, 10).Select(p => rand.Next(0, 100)).Where(p => p > 9 && p < 80).Average();
Console.WriteLine(result.ToString("N2"));