using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace Test1{    class Program{        static void Main(string[] args){            object ob;            ob = 10;            Console.WriteLine(ob.GetType());            ob = true;            Console.WriteLine(ob.GetType());            ob = 10.13m;            Console.WriteLine(ob.GetType());            Console.ReadLine();        }    }}

namespace Test1{    class Program{        static void Main(string[] args){            int a = 10;            if (a is bool) //表达式 is 类型                 Console.WriteLine("yes");            else                Console.WriteLine("no");            object[] nums = new object[3];            nums[0] = 123;            nums[1] = "hell";            nums[2] = "字符串";            for (int i = 0; i < nums.Length; ++i) {                //表达式 as 引用类型       当as指定的转换不能实现时，运算结果为null                string s = nums[i] as string; //将数组nums的对应元素转换成字符串                Console.WriteLine("nums[{0}]", i);                if (s != null) {                    Console.WriteLine("not a null");                } else {                    Console.WriteLine("is a null");                }            }            bool k1 = 5 > 3 ? true : false;            Console.WriteLine(k1);                        Console.ReadLine();        }    }}