.NET中类和结构的区别

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

namespace ConsoleApplication1
{
    public enum Gender
    { 
        男,
        女
    }

    public struct sPerson 
    {
        public string name;
        public int age;
        public Gender sex;

        public void say() {
            Console.WriteLine("Hello , my name is {0} , i am {1} years old", this.name,this.age);
        }

        public sPerson(string name,int age,Gender sex) {
            this.name = name;
            this.age = age;
            this.sex = sex;
        }

        public sPerson() {
            this.name = "default";
            this.age = 0;
            this.sex = Gender.男;  
        }
    }

    public class Person
    {
        public string name;
        public int age;
        public Gender sex;

        public void say() {
            Console.WriteLine("Hello , my name is {0}, i am {1} years old", this.name,this.age);
        }

        public Person(string name,int age,Gender sex) {
            this.name = name;
            this.age = age;
            this.sex = sex;
        }

        public Person() {
            this.name = "default";
            this.age = 0;
            this.sex = Gender.男;
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            sPerson sp1 = new sPerson("jack", 25, Gender.男);
            sp1.say();
            sPerson sp2 = new sPerson();
            sp2.say();
            Person p1 = new Person();
            p1.say();
            Person p2 = new Person("mick", 30, Gender.男);
            p2.say();
            Console.ReadKey();
        }
    }
}