字段加GetSet方法可以加限制

访问和设置 

C# 的set和get方法基本相同。

 class Vector3
    {
        private double x;
        private double y;
        private double z;
        public double Length()       
        {
            double res=Math.Sqrt(x * x + y * y + z * z);
            Console.WriteLine("res="+res);
            return res;
        }
        public void SetX(double temp)
        {
            if (temp<0)
            {
                return;
            }
            x = temp;
        }
        public void SetY(double temp)
        {
            if (temp < 0)
            {
                return;
            }
            y = temp;
        }
        public void SetZ(double temp)
        {
            if (temp < 0)
            {
                return;
            }
            z = temp;
        }
        public double GetX()
        {
            return x;
        }
        public double GetY()
        {
            return y;
        }
        public double GetZ()
        {
            return z;
        }
    }class Student
    {
        public string name;
        public int age;
        public string address;
        public string createTime;

        public void Show()
        {
            Console.WriteLine("名字：" + name);
            Console.WriteLine("地址：" + address);
            Console.WriteLine("年龄：" + age);
            Console.WriteLine("创建日期：" + createTime);

        }
    }
    class  Vehicle
    {
        public string brand;
        public double speed;
        public double maxSpeed;
        public double weight;
        public void Run()
        {
            Console.WriteLine("车在跑");
        }
        public void Stop()
        {
            Console.WriteLine("刹车");
        }
       
       
    }
    class Program
    {
        static void test02()
        {
            Vehicle car1 = new Vehicle();
            car1.Run();
            car1.Stop();
            Vector3 v1 = new Vector3();
            //v1.SetX(5.6);
            v1.SetY(4.5);
            v1.SetZ(8.45);
            //Console.WriteLine(v1.GetX());
            v1.SetX(-5);//默认是0，没有改变成负数
            Console.WriteLine(v1.GetX());
            Console.WriteLine(v1.Length());
        }
        static void test01()
        {
            Student stu1 = new Student();//声明对象+实例化对象
            Student stu2;//声明对象
            stu1.name = "李四";
            stu1.address = "山西";
            stu1.age = 18;
            stu1.createTime = "11月23日";
            stu1.Show();
            stu2 = new Student();//实例化对象
            
        }
        static void Main(string[] args)
        {
            //test01();
            test02();
        }
    }