C# 강좌 Day-18 인덱서

인덱서에서는 클래스나 구조체의 인스턴스를 배열처럼 인덱싱할 수 있습니다. 인덱싱 값은 형식이나 인스턴스 멤버를 명시적으로 지정하지 않고도 설정하거나 검색할 수 있습니다. 인덱서는 해당 접근자가 매개 변수를 사용한다는 점을 제외하면 속성과 유사합니다.

https://docs.microsoft.com/ko-kr/dotnet/csharp/programming-guide/indexers/

인덱서 - C# 프로그래밍 가이드

using System;
using System.Collections;

namespace Step51
{
    public enum eRacesOfStarCraft
    {
        Zerg, Protoss, Terran
    }
    public class RacesCollection2
    {
        eRacesOfStarCraft[] races = {
            eRacesOfStarCraft.Zerg, eRacesOfStarCraft.Protoss, eRacesOfStarCraft.Terran
        };
        public int this[eRacesOfStarCraft race]
        {
            get {
                return this.FindIndex(race);
            }
        }

        public int FindIndex(eRacesOfStarCraft race)
        {
            for (int i = 0; i < this.races.Length; i++) {
                if(this.races[i] == race)
                {
                    return i;
                }
            }
            return -1;
        }
    }

    class RacesCollection {
        string[] races = { "Zerg", "Protoss", "Terran" };
        public int this[string race] {
            get {
                return this.FindIndex(race);
            }
        }
        private int FindIndex(string race) {
            for (int i = 0; i < this.races.Length; i++) {
                if (race == this.races[i]) {
                    return i;
                }
            }
            return -1;
        }
    }
    public class Marine { }
    public class MarineEnumerator : IEnumerator
    {
        private Marine[] marines;
        private int pointer = -1;
        public MarineEnumerator(Marine[] marines)
        {
            this.marines = marines;
        }
        public object Current => this.marines[this.pointer];

        public bool MoveNext()
        {
            this.pointer++;
            return this.pointer < this.marines.Length;
        }

        public void Reset()
        {
            this.pointer = -1;
        }
    }
    public class MarineGroup : IEnumerable {
        private Marine[] marines;
        public Marine this[int i]
        {
            get { return this.marines[i]; }
            set { this.marines[i] = value; }
        }

        public MarineGroup(Marine[] marines)
        {
            this.marines = new Marine[marines.Length];
            for (int i = 0; i < marines.Length; i++) {
                this.marines[i] = marines[i];
            }
        }

        public IEnumerator GetEnumerator()
        {
            return new MarineEnumerator(this.marines);
        }
    }
    class NameCollection
    {
        private string[] names;

        public string this[int i] {
            get { return this.names[i]; }
            set { this.names[i] = value; }
        }

        public NameCollection(int capacity)
        {
            this.names = new string[capacity];
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            //NameCollection collection = new NameCollection(5);
            //collection[0] = "홍길동";


            //Marine[] marines = {
            //    new Marine(),
            //    new Marine(),
            //    new Marine()
            //};

            //MarineGroup group = new MarineGroup(marines);
            //var marine = group[2];
            //Console.WriteLine(marine);
            //foreach (var m in group) {
            //    Console.WriteLine(m);
            //}

            //RacesCollection collection = new RacesCollection();
            //var index = collection["Zerg"];
            //Console.WriteLine(index);     //0


            RacesCollection2 collection = new RacesCollection2();
            var index = collection[eRacesOfStarCraft.Protoss];
            Console.WriteLine(index);   //1

        }
    }
}