C# 可空值类型详解编程语言

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
 
namespace 可空值类型 
{ 
    class Program 
    { 
        static void Main(string[] args) 
        { 
            int? a = null; 
            int? b = 5; 
            Console.WriteLine(a);//空 
            Console.WriteLine(b);//5 
            Console.WriteLine(a == b);//false 
            Console.ReadKey();             
        } 
 
    } 
 
 
}