【C# Lab】0003 《C#入門經典》Ch11 集合、比較和轉換 章後習題

【題目描述】


【我的解答】

using System;
using System.Collections;

namespace Ch11_Exercises
{
    class Person:ICloneable
    {
        private string name;
        private int age;

        public Person() : this("default Name", 20)
        {

        }
        public Person(string name, int age)
        {
            this.name = name;
            this.age = age;
        }
        public string Name
        {
            get { return name; }
            set { name = value; }
        }
        public int Age
        {
            get { return age; }
            set { age = value; }
        }

        public static bool operator >=(Person p1, Person p2)
        {
            return p1.Age >= p2.Age;
        }
        public static bool operator <(Person p1, Person p2)
        {
            return !(p1>=p2);
        }
        public static bool operator <=(Person p1,Person p2)
        {
            return p1.Age <= p2.Age;
        }
        public static bool operator >(Person p1, Person p2)
        {
            return !(p1<=p2);
        }
        /* 
        public static bool operator ==(Person p1,Person p2)
        {
            return p1.Age == p2.Age;
        }
        public static bool operator !=(Person p1,Person p2)
        {
            return !(p1 == p2);
        }
        public override bool Equals(object obj)
        {
            if(obj is Person)
            {
                return age == (obj as Person).age;
            }
            else
            {
                throw new ArgumentException("Cannot compare Person objects with objects of type"
                    +obj.GetType().ToString());
            }
        }
        public override int GetHashCode()
        {
            return age;
        }
        */
        public object Clone()
        {
            return this.MemberwiseClone();
        }
    }
    class People :DictionaryBase,ICloneable
    {

        public IEnumerable Ages
        {
            get
            {
                foreach(object p in Dictionary.Values)
                {
                    yield return (p as Person).Age;
                }
            }
        }
        public void Add(Person newPerson)
        {
            Dictionary.Add(newPerson.Name,newPerson);
        }
        public void Remove(string newID)
        {
            Dictionary.Remove(newID);
        }
        public Person this[string personName]
        {
            get { return (Person)Dictionary[personName]; }
            set { Dictionary[personName] = value; }
        }

        public Person[] GetOldest()
        {
            Person oldestPerson = null;
            People oldestPeople = new People();
            Person currentPerson;
            foreach(DictionaryEntry p in Dictionary)
            {
                currentPerson = p.Value as Person;
                if(oldestPerson == null)//最好別重載==，因爲這裏我們不希望重載
                {
                    oldestPerson = currentPerson;
                    oldestPeople.Add(currentPerson);
                }
                else
                {
                    if (currentPerson > oldestPerson)
                    {
                        oldestPerson = currentPerson;
                        oldestPeople.Clear();
                        oldestPeople.Add(currentPerson);
                    }
                    else if(currentPerson >= oldestPerson)//未重載==號
                    {
                        oldestPeople.Add(currentPerson);
                    }
                }
            }
            Person[] ret = new Person[oldestPeople.Count];
            int copyIndex = 0;
            foreach(DictionaryEntry p in oldestPeople)
            {
                ret[copyIndex++] = p.Value as Person;
            }
            return ret;
        }

        public object Clone()
        {
            People people = new People();
            foreach(DictionaryEntry p in Dictionary)
            {
                people.Add((p.Value as Person).Clone() as Person);
            }
            return people;
        }
        
        /* //shallow copy
        public object Clone()
        {
            return this.MemberwiseClone();
        }
        */
    }
    class Test
    {
        static void Main(string[] args)
        {
            People personCollection = new People();
            personCollection.Add(new Person("QiuQiu",20));
            personCollection.Add(new Person("BiuBiu", 21));
            personCollection.Add(new Person("PiuPiu", 21));
            personCollection.Add(new Person("NiuNiu", 16));
            Console.WriteLine("members in personCollection:");
            foreach (DictionaryEntry p in personCollection)
            {
                Person cur = p.Value as Person;
                Console.WriteLine($"Name:{cur.Name},Age:{cur.Age}");
            }
            Console.WriteLine("01:Search personCollection[\"PiuPiu\"]");
            Console.WriteLine($"Name:{personCollection["PiuPiu"].Name},Age:" +
                $"{personCollection["PiuPiu"].Age}");
            //personCollection.Remove("PiuPiu");
             Console.WriteLine("02: is BiuBiu younger than QiuQiu?");
            if (personCollection["BiuBiu"] < personCollection["QiuQiu"])
                Console.WriteLine("yes");
            else
                Console.WriteLine("no");
            //3
            Console.WriteLine("03:OldestPerson");
            Person[] oldests = personCollection.GetOldest();
            foreach(Person p in oldests)
            {
                Console.WriteLine($"name:{p.Name},Age:{p.Age}");
            }
             //4
            Console.WriteLine("04:Deep Copy from people to newPeople");
            People newPeople = personCollection.Clone() as People;
            try
            {
                personCollection.Remove("PiuPiu");
                personCollection["QiuQiu"].Name = "XiuXiu";
            }
            catch(Exception e)
            {
                Console.WriteLine(e.Message);
            }
            Console.WriteLine("people：");
            foreach (DictionaryEntry p in personCollection)
            {
                Console.WriteLine($"Name:{(p.Value as Person).Name}," +
                    $"Age:{(p.Value as Person).Age}");
            }
            Console.WriteLine("newPeople：");
            foreach(DictionaryEntry p in newPeople)
            {
                Console.WriteLine($"Name:{(p.Value as Person).Name}," +
                    $"Age:{(p.Value as Person).Age}");
            }
            
            Console.WriteLine("05:IEnumerable");
            Console.WriteLine("personCollection Ages:");
            foreach(int age in personCollection.Ages)
            {
                Console.WriteLine(age.ToString());
            }
            Console.ReadKey();
        }
    }
}

【Output】