C#：定义并实现一个公民类Citizen

//author---Henan University.software engineering.李思佳
using System;

namespace ConsoleApp3
{
    public enum Gender 
    {
        男,
        女
    }
    public class Citizen
    { 
        public string ID { set; get; }
        public string Name { set; get; }
        public Gender G { set; get; }
        public int Age;
        public string Birthplace { set; get; }
        public string Familyaddress { set; get; }

        public int AGE //属性
        {
            get
            {
                return Age;
            }
            set
            {
                if (value <= 0 || value > 150)
                   Console.WriteLine("您输入的年龄不合法!（将修改为默认值）");
                 else
                   Age = value;                            
            }  //set
        }//age
        public Citizen()
        {
            ID = "0000";
            Name = "xxx";
            G = Gender.男;
            Age = 20;
            Birthplace = "xx省xx市";
            Familyaddress = "xx省xx市";
        }
        public void Input(string id,string name,Gender g,int age,string birthplace,string familyaddress)
        {
            ID = id;
            Name = name;
            G = g;
            AGE = age;
            Birthplace = birthplace;
            Familyaddress = familyaddress;
        }
        public void Print()
        {
            Console.WriteLine("该公民的信息如下：");
            Console.WriteLine("身份证号:" + ID);
            Console.WriteLine("姓名:" + Name);
            Console.WriteLine("性别:" + G);
            Console.WriteLine("年龄:" + Age);
            Console.WriteLine("籍贯:" + Birthplace);
            Console.WriteLine("家庭住址:" + Familyaddress);
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            Citizen c0 = new Citizen();
            Console.WriteLine("the example person:");
            c0.Print(); 
            Console.WriteLine("");

            Citizen c1 = new Citizen();
            Console.WriteLine("the first person:");
            c1.Input("412825", "lisi", Gender.女, 18, "河南省", "河大");
            c1.Print();
            Console.WriteLine("");

            Citizen c2 = new Citizen();
            Console.WriteLine("the second person:");
            c2.Input("412826", "zhangsan", Gender.男, -1, "河南省", "郑大");
            c2.Print();
            Console.WriteLine("......");

            Console.ReadLine();
        }
    }
}