新手求教。

Question

在学习中遇到的问题，在C#入门经典第三版的11章第一个例子。我照打但是有错误，希望大家帮忙解决。
添加了3个类。using System;
using System.Collections.Generic;
using System.Text;namespace ch1101
{
        public abstract class Animal
        {
            protected string name;
            public string name
            {
                get
                {
                    return name;
                }
                set
                {
                    name = value;
                }
            }
            public Animal()
            {
                name = "the animal with no name";
            }
            public void feed()
            {
                Console.WriteLine("{0} has been fed",name);
            }
        }
}

Answer 1

第二。三个类using System;
using System.Collections.Generic;
using System.Text;namespace ch1101
{
        public class Cow : Animal
        {
            public void Milk()
            {
                Console.WriteLine("{0} has been milked", name);
            }
            public Cow(string newname)
                : base(newname)
            {            }
        }
}
using System;
using System.Collections.Generic;
using System.Text;namespace ch1101
{
    public class Chicken:Animal
    {
            public void LayEgg()
            {
                Console.WriteLine("{0} has laid an egg", name);
            }
            public Chicken(string newname): base(newname)
            {            }
    }
}

Answer 2

这个是program.cs中的代码。using System;
using System.Collections.Generic;
using System.Text;
using System.Collections;namespace ch1101
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("create an array type collection of animal" +
                "object and use it:");
            Animal[] animalarray = new Animal[2];
            Cow mycow1 = new Cow("Deirerd");
            animalarray[0] = mycow1;
            animalarray[1] = new Chicken("ken");            foreach (Animal myanimal in animalarray)
            {
                Console.WriteLine("new {0} object add to array collection,"+
                    "name={1}",myanimal.ToString(),myanimal.name);
            }
            Console.WriteLine("array colletion contains {0} objects.",animalarray.Length);
            animalarray[0].feed();
            ((Chicken)animalarray[1]).LayEgg();
            Console.WriteLine();            Console.WriteLine("create an arraylist type collection of animal" +
                "object and use it:");
            ArrayList animalarraylist = new ArrayList();
            Cow mycow2 = new Cow("hayley");
            animalarraylist.Add(mycow2);
            animalarraylist.Add(new Chicken("roy"));
            foreach (Animal myanimal in animalarraylist)
            {
                    Console.WriteLine("new {0} object add to arraylist collection,"+
                      "name={1}",myanimal.ToString(),myanimal.name);                
            }
            Console.WriteLine("array colletion contains {0} objects.", animalarraylist.Count);
            ((Animal)animalarraylist[0]).feed();
            ((Chicken)animalarraylist[1]).LayEgg();
            Console.WriteLine();            Console.WriteLine("additional manipulation  of arraylist:");
            animalarraylist.RemoveAt(0);
            ((Animal)animalarraylist[0]).feed();
            animalarraylist.AddRange(animalarray);
            ((Chicken)animalarraylist[2]).LayEgg();
            Console.WriteLine("the animal called {0} is at index {1},",
                              mycow1.name,animalarraylist.IndexOf(mycow1));
            mycow1.name = "janice";
            Console.WriteLine("the animal is now called {0}.",
                               ((Animal)animalarraylist[1]).name  );
            Console.ReadKey();
        }
    }
}

Answer 3

在ANIMAL类中有2个 string 类型的name，想问问是不是应该改一个啊？

Answer 4

  protected string _name;
            public string name
            {
                get
                {
                    return name;
                }
                set
                {
                    name = value;
                }
            }建议不要使用一样的名字来定义属性和字段

Answer 5

我想也是。可能是PDF上写错了吧。但是改完又有新问题。
提示"animal"方法中没有采用"1"个参数的重载。请问这个怎么解决？

Answer 6

base(newname) 这个不是说的animal吗，它的构造函数没有参数的，所以newname没用。或者把这句删了，或者类一修改一下。