struct VS class

struct和class最本质的区别是：struct是值类型，而class则是引用类型；struct继承自System.ValueType类，class继承自System.Object类
struct一般用于存储数据，值保存于堆栈中，class则是面向对象一个重要概念，着重体现行为，当new 一个实例的时候，对象保存的是实际数据的引用地址，而对象实际数据则保存于堆中
struct不能继承另一个结构，也不能从class继承,没有继承特性，结构的成员不能用protected修饰符，但是struct可以继承接口；class则既可以从类继承，也可以从
接口继承，但不可以从struct继承，也不能继承自多个类，但可以继承自多个接口;struct 可以重载System.Object类的ToString(),Equals(),GetHashCode()方法
struct不能自定义的显式声明的无参构造函数，但具有默认的无参构造函数，功能就是将成员初始化为0的等价值
结构还可以包含构造函数、常量、字段、方法、属性、索引器、运算符、事件和嵌套类型，但如果同时需要上述几种成员，则应当考虑改为使用类作为类型；struct通常用来封装小型相关变量组.
Demo:
  interface IBook
    {
        void ShowBook();
    }
   
 public struct Book:IBook
    {
        public string _title;
        public string _author;
        public decimal _price;
        public bool _type;
        //public Book()
        //{

        //}
        public Book(string title, string author, decimal price,bool type)//    在控制离开构造函数之前，字段“struct_class.Book._type”必须完全赋值   
        {
            this._title = title;
            this._author = author;
            this._price = price;
            this._type = type;
        }
        public string Title
        {
            get
            {
                return this._title;
            }
        }
        public string Author
        {
            get
            {
                return this._author;
            }
        }
        public decimal Price
        {
            get
            {
                return this._price;
            }
        }
        public bool Type
        {
            get
            {
                return this._type;
            }
        }
        public void ShowBook()
        {
            if (Type)
            {
                Console.WriteLine("This is {0} and its author is {1} and its price is {2}.It is an english book",this.Title,this.Author,this.Price);
            }
            else
            {
                Console.WriteLine("This is {0} and its author is {1} and its price is {2}.It is an chinese book", this.Title, this.Author, this.Price);
            }
        }
     public override int GetHashCode()
       {
           return base.GetHashCode();
       }
       public override bool Equals(object obj)
       {
           return base.Equals(obj);
       }
       public override string ToString()
       {
           return base.ToString();
       }
       
       
    }
 static void Main(string[] args)
        {
            //Book b = new Book();
            Book b = new Book("Love", "zhangxi24",(decimal)20.5, true);
            b.ShowBook();
        }