myList.cs

c#
using System;
using System.Collections.Generic;
using System.Text;

namespace MyList列表 {
  class MyList < T > {
    private T[] data = new T[0]; //data null
    private int count = 0; // 元素个数 数据个数

    public int Capacity //获取容量大小
    {
      get {
        return data.Length;
      }
    }
    public int Count //获取元素个数
    {
      get {
        return count;
      }
    }

    public void Add(T item) //添加元素
    {
      if (data.Length == 0) {
        data = new T[4];
      }
      if (data.Length == count) //添加元素之前 ，先判断数组是否已经满
      {
        T[] temp = new T[count * 2];
        for (int i = 0; i < data.Length; i++) {
          temp[i] = data[i];
        }
        data = temp;
      }
      data[count] = item;
      count++;
    }

    public T this[int index] //访问元素
    {
      get {
        if (index < 0 || index > count - 1) { //抛出异常
          throw new ArgumentOutOfRangeException("索引参数超出范围了");
        }
        return data[index];
      }
      set {
        data[index] = value;
      }
    }

    public void Insert(int index, T item) //插入元素
    {
      if (index < 0 || index > count - 1) //判断是否存在索引
      {
        throw new ArgumentOutOfRangeException("索引参数超出范围了");
      }

      for (int i = count - 1; i > index - 1; i--) {
        // count-1     index
        data[i + 1] = data[i];
      }
      data[index] = item;
      count++;
    }
    public void RemoveAt(int index) //移除指定位置元素
    {
      if (index < 0 || index > count - 1) {
        throw new ArgumentOutOfRangeException("索引参数超出范围了");
      }
      for (int i = index + 1; i < count; i++) {
        // index+1   count-1
        data[i - 1] = data[i];
      }
      count--;
    }
    public int IndexOf(T item) //从前往后获取元素所在的索引位置
    {
      int index = -1;
      for (int i = 0; i < count; i++) { // ToString Equals
        if (item.Equals(data[i])) {
          index = i;
          break;
        }
      }
      return index; //从前往后
    }

    public int LastIndexOf(T item) //从后往前获取元素所在的索引位置
    {
      int index = -1;
      for (int i = count - 1; i >= 0; i--) { // ToString Equals
        if (item.Equals(data[i])) {
          index = i;
          break;
        }
      }
      return index; //从后往前
    }

    public void Sort() //排序
    {
      Array.Sort(data, 0, count); //0, count  指范围
    }
  }
}

Program.cs

c#

using System;
using System.Collections.Generic;

namespace MyList列表 {
  class Program {
    static void Main(string[] args) {
      // 1.Capacity 获取容量⼤⼩
      MyList < int > list = new MyList < int > ();
      Console.WriteLine(list.Capacity);

      // 2.Add()⽅法添加元素
      list.Add(1);
      list.Add(2);
      list.Add(3);
      list.Add(4);
      list.Add(5);
      list.Add(4);

      // 5.Count属性访问元素个数
      Console.WriteLine(list.Count);
      //遍历集合
      for (int i = 0; i < list.Count; i++) {
        Console.Write(list[i] + " ");
      }

      // 3.Insert()⽅法插⼊元素
      list.Insert(2, 100);
      for (int i = 0; i < list.Count; i++) //遍历集合
      {
        Console.Write(list[i] + " ");
      }
      Console.WriteLine();

      // 4.[index]访问元素(索引器) 
      int temp1 = list[10];
      int temp2 = list[-1];
      List < int > l = new List < int > ();
      int temp = l[-1];

      // 6.RemoveAt()⽅法移除指定位置的元素
      list.RemoveAt(3);
      for (int i = 0; i < list.Count; i++) //遍历集合
      {
        Console.Write(list[i] + " ");
      }
      Console.WriteLine();

      // 7.IndexOf()⽅法取得⼀个元素所在列表中的索引位置
      Console.WriteLine(list.IndexOf(4)); //从前往后搜索
      Console.WriteLine(list.LastIndexOf(4)); //从后往前搜索

      // 8.Sort()对列表中是元素进⾏从⼩到⼤排序
      list.Sort();
      for (int i = 0; i < list.Count; i++) //遍历集合
      {
        Console.Write(list[i] + " ");
      }
      Console.WriteLine();
    }
  }
}