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

namespace __9
{
    class Program
    {
        static void Main(string[] args)
        {
            int a = 3;
            testprimitive(a);
            Console.WriteLine(a);              //3

            ArrayList l = new ArrayList();
            Console.WriteLine(l.Count);            //0
           
            textobjectlist(l);
            Console.WriteLine(l.Count);        //?2
            print(l);

            Console.WriteLine("-------------");
            ArrayList ll = new ArrayList();
            ll.Add("major");
            Console.WriteLine(ll.Count);           //1
            print(ll);
            Console.WriteLine("--------------");
            textobjectlist2(ll);
            Console.WriteLine(ll.Count);       //?1
            print(ll);

            Console.WriteLine("....---------------");
           
            string s = "jack";
            teststring(s);
            Console.WriteLine(s); //jack
        }

        private static void testprimitive(int a)
        {
            a *= 2;
        }
        private static void textobjectlist(ArrayList l)
        {
            l.Add("jumbo");
            l.Add("jumbo2");
        }
        private static void textobjectlist2(ArrayList l)
        {
            l = null;                                            //l 指向null引用，以前的那个对象并没有变
            //l.Add("a");
            //l.Add("b");
        }
        private static void teststring(string s)
        {
            s = "john";
        }

        private static void print(ArrayList l)
        {
            foreach(string s in l)
            {
                Console.WriteLine(s);
            }
        }
    }
}

评论