实现栈类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;

namespace ConsoleApplication15
{
    class MyStack  //自定义的栈
    {
        private int count;
        private int index; //定位标识
        ArrayList arr; //声明，ArrayList可以动态改变大小，里面元素类型为object
        public MyStack()
        {
            arr = new ArrayList(); //分配相应内存
            this.index = -1;
        }
        public int getCount  //查看栈中元素个数
        {
            get
            {
                return this.arr.Count;
            }
        }
        public object pop() //出栈
        {
            object o = arr[index];
            arr.RemoveAt(index);
            index--;
            return o;
        }
        public void push(object o)  //进栈
        {
            arr.Add(o);
            index++;
        }
        public object peek()  //查看栈顶元素
        {
            return arr[index];
        }
        public void clear()  //清空栈
        {
            arr.Clear();
            index = -1;
        }
    }
    class Program
    {       
        static void Main(string[] args)
        {
            MyStack stack = new MyStack();
            Console.WriteLine("执行进栈操作");
            stack.push(1);
            stack.push(2);
            stack.push(3);
            Console.WriteLine("进栈操作结束");
            Console.WriteLine("栈顶元素为：{0}",stack.peek());
            Console.WriteLine("栈中元素共有：{0}个",stack.getCount);
            Console.WriteLine("执行出栈操作：");
            while (stack.getCount > 0)
            {
                Console.WriteLine(stack.pop());
            }
            Console.WriteLine("出栈操作后，栈中元素共有：{0}个",stack.getCount);
            Console.Read();
        }
    }
}