C# 参数传递 引用类型与值类型的值传递和引用传递

///变长参数的例子
     class Program
    {
        static void Main(string[] args)
        {
            ShowAgeSum("w", 1, 2, 3, 4);
            ShowAgeSum("h", 1, 1, 1);
            ShowAgeSum("c", 99, 1, 2, 3, 4, 1, 0, 0, 0, 0, 0, 0, 100000);
            Console.Read();
        }

        static void ShowAgeSum(string team, params int[] ages)
        {
            int ageSum = 0;
            for (int i = 0; i < ages.Length; i++)
                ageSum += ages[i];
            Console.Write("{0}'s age is {1}\r\n",team,ageSum);
        }
    }
    ///值类型参数 按值传递 和按引用传递的区别 
    class Program
    {
        static void Main(string[] args)
        {
            int a = 0;
            Add(a);
            Console.WriteLine(a);
            Add(ref a);
            Console.WriteLine(a);
            Console.Read();
        }

        static void Add(int i)
        {
            i = i + 10;
            Console.WriteLine(i);
        }

        static void Add(ref int i)
        {
            i = i + 10;
            Console.WriteLine(i);
        }
    }
    结果：10,0,10,10；
    
    ///引用类型参数 按值传递和按引用传递的区别
    class Program
    {
        static void Main(string[] args)
        {
            ArgsByRef a = new ArgsByRef();
            Add(a);
            Console.WriteLine(a.i);
            Add(ref a);
            Console.WriteLine(a.i);
            Console.Read();
        }

        static void Add(ArgsByRef a)
        {
            a.i = 20;
            Console.WriteLine(a.i);
        }

        static void Add(ref ArgsByRef a)
        {
            a.i = 30;
            Console.WriteLine(a.i);
        }

       
    }
    class ArgsByRef
    {
        public int i = 10;
    }
结果 ：20,20,30,30；

///字符串参数的按值与按引用传递 与 值类型一致 (string 是引用类型）
 class Program
    {
        static void Main(string[] args)
        {
            string a = "Old String";
            Add(a);
            Console.WriteLine(a);
            Add(ref a);
            Console.WriteLine(a);
            Console.Read();
        }

        static void Add(string a)
        {
            a = "new String";
            Console.WriteLine(a);
        }

        static void Add(ref string a)
        {
            a = "new String";
            Console.WriteLine(a);
        }
    }
    结果：new String, Old String,new String,new String;