C#中的操作符重载

细心的朋友可能发现，C#虽然可以重载操作符，但和C++比较起来，却有很大的不同。定义的时候重载操作符方法必须是static，而且至少有一个参数（一目和二目分别是一个和两个），C#和C++比起来，最重要的特征是：<、>；==、!=；true、false必须成对出现，即重载了“<”就必须重载“>”，重载了“==”就必须重载“！=”，重载了“true”就必须重载“false”；另外，还必须实现基类object的两个虚方法：GetHashCode()和Equals(object obj)。

 

    以下是程序代码，有些地方写得不完善，只能说仅仅说明了问题，不对之处请指教：

using System;

using System.Xml;

 

namespace ConsoleApplication8

{

    /// <summary>

    /// 姓名类

    /// </summary>

    class Namer

    {

        private string FirstName;

        private string LastName;

 

        public Namer()

        {

            this.Init(null,null);

        }

 

        public Namer(string fn,string ln)

        {

            this.Init(fn,ln);

        }

 

        private void Init(string fn,string ln)

        {

            this.FirstName=fn;

            this.LastName=ln;

        }

 

        /// <summary>

        /// 重载运算符true

        /// </summary>

        /// <param name="n"></param>

        /// <returns>如果姓名中姓或名有一个为空，就返回假</returns>

        public static bool operator true(Namer n)

        {

            if(n.FirstName==null || n.LastName==null)

                return false;

            else

                return true;

        }

 

        /// <summary>

        /// 重载运算符false

        /// </summary>

        /// <param name="n"></param>

        /// <returns></returns>

        public static bool operator false(Namer n)

        {

            if(n.FirstName==null || n.LastName==null)

                return false;

            else

                return true;

        }

 

        /// <summary>

        /// 重载运算符==

        /// </summary>

        /// <param name="n1"></param>

        /// <param name="n2"></param>

        /// <returns></returns>

        public static bool operator ==(Namer n1,Namer n2)

        {

            if(n1.FirstName==n2.FirstName && n1.LastName==n2.LastName)

                return true;

            else

                return false;

        }

 

        /// <summary>

        /// 重载运算符！=

        /// </summary>

        /// <param name="n1"></param>

        /// <param name="n2"></param>

        /// <returns></returns>

        public static bool operator !=(Namer n1,Namer n2)

        {

            if(n1.FirstName!=n2.FirstName || n1.LastName !=n2.LastName)

                return true;

            else

                return false;

        }

 

 

        /// <summary>

        /// 重载运算符>

        /// </summary>

        /// <param name="n1"></param>

        /// <param name="n2"></param>

        /// <returns></returns>

        public static bool operator >(Namer n1,Namer n2)

        {

            return (n1.FirstName.CompareTo(n2.FirstName)>0 && n1.LastName.CompareTo(n2.LastName)>0);

        }

 

        /// <summary>

        /// 重载运算符<

        /// </summary>

        /// <param name="n1"></param>

        /// <param name="n2"></param>

        /// <returns></returns>

        public static bool operator <(Namer n1,Namer n2)

        {

            return (n1.FirstName.CompareTo(n2.FirstName)<0 && n1.LastName.CompareTo(n2.LastName)<0);

        }

 

        /// <summary>

        /// 重写方法，必须有,后面的111是乱加的，你也可以写其它的

        /// </summary>

        /// <returns></returns>

        public override int GetHashCode()

        {

            return base.GetHashCode()*111;

        }

 

        /// <summary>

        /// 重写方法，必须有

        /// </summary>

        /// <param name="obj"></param>

        /// <returns></returns>

        public override bool Equals(object obj)

        {

            return base.Equals (obj);

        }

 

        /// <summary>

        /// 重写方法，必须有

        /// </summary>

        /// <returns></returns>

        public override string ToString()

        {

            return "姓:"+this.FirstName+" 名:"+this.LastName;

        }

 

 

        public static void Main()

        {

            Namer n1=new Namer("li","zanhong");

            Namer n2=new Namer("ahang","aan");

            //Namer n2=new Namer("li","zanhong");

 

            if(n1==n2)

                Console.WriteLine("一样的名字");

            else

                Console.WriteLine("不一样的名字");

            /////////////////////////////////////

            if(n1!=n2)

                Console.WriteLine("不一样的名字成立");

            else

                Console.WriteLine("同样的名字成立");

            /////////////////////////////////////

            if(n1>n2)

                Console.WriteLine(n1.ToString()+">"+n2.ToString());

            else if(n1<n2)

                Console.WriteLine(n1.ToString()+"<"+n2.ToString());

            else

                Console.WriteLine("没有正确比较");

 

            Console.ReadLine();

        }

 

    }

}