C#（简单递归）和实现IComparable接口

递归：

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

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("输入一个数,计算阶乘");
            int m = int.Parse(Console.ReadLine());
            int sumc = 0;
            for (int i = 0; i <= m; i++)
            {
                sumc += fun(i);
            }
            for (int i = 0; i < m; i++)
            {
                Console.Write("{0}!+", i);
            }
            Console.WriteLine("{0}!={1}", m, sumc);

            Console.ReadLine();
        }

        public static int fun(int n)
        {
            if (n < 1)
            {
                return 0;
            }
            if (n == 1)
            {
                return 1;
            }
            return n * fun(n - 1);
        }
    }
}

　　实现IComparable和必需的CompareTo方法。

public  class Temperature:IComparable
    {

       protected double TemperatureF;

        public int CompareTo(object obj)
        {
            if (obj == null) return 1;
            Temperature otherTemprature = obj as Temperature;
            if (otherTemprature != null)
                return this.TemperatureF.CompareTo(otherTemprature.TemperatureF);
            else
                throw new ArgumentException("Object is not a Temperature");

        }

        public double Fahrenheit 
        {
            get { return this.TemperatureF; }
            set { this.TemperatureF=value;}
        }

        public double Celsius
        {
            get { return (this.TemperatureF-32)*(5.0/9); }
            set { this.TemperatureF = (value *9.0/5)+32; }
        }
    }

 static void Main(string[] args)
        {
            ArrayList temperatures = new ArrayList();
            Random random = new Random();
            for (int i = 0; i < 10; i++)
            {
                int degrees = random.Next(0, 100);
                Temperature temp = new Temperature();
                temp.Fahrenheit = degrees;
                temperatures.Add(temp);
            }

            temperatures.Sort();
            foreach (Temperature item in temperatures)
            {
                Console.WriteLine(item.Fahrenheit);
            }
        }