以下程序的输出结果是 。 using System; namespace aaa { public class Person { private int age = 0; public int Age { get { return age; } set { if (value>=18) Console.WriteLine("成年人"); else Console.WriteLine("非成年人"); age = value; } } } public class People:Person { public People() { Console.Write("不得入内"); } } public class Program { public static void Main() { People Shang = new People(); Shang.Age=25; } } }