using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Threading;namespace ConsoleApplication1
{class Program{static void Main(string[] args){//第一种// Student st = new Student();//DateTime birthdate = new DateTime(2003, 5, 28); //第二种//Student st2 = new Student("lily",birthdate);//第三种//goodStudent goodst = new goodStudent();//第四种// goodStudent goodst2 = new goodStudent("harfla");//第五种// goodStudent goodst3 = new goodStudent("david",new DateTime(1990,6,18) ,"Tqing");
Console.ReadKey();}}
}public class Student {protected int Age;public string Name;public DateTime   birthDate;public int GetAge(){int ts = DateTime.Now.Year - birthDate.Year;return ts;}public Student(){Console.WriteLine("默认的构造函数");}public Student(string name, DateTime  birthDt) {this.Name = name;this.birthDate = birthDt;Console.WriteLine("带参数构造函数");Console.WriteLine("name:{0}--birthdate:{1}",Name,birthDate.ToString("yyyy-MM-dd"));}}public class goodStudent : Student {static DateTime birthdate = new DateTime(2003, 5, 20);  public int Score;public string University;public goodStudent(): base(){ }public goodStudent(string name, DateTime birthDat, string school): base(name, birthDat){this.Age = DateTime.Now.Year - birthDate.Year;this.University = school;Console.WriteLine("name:{0}--birth:{1}--age:{2}", Name, birthDate.ToString("yyyy-MM-dd"), Age);Console.WriteLine("university--{0}", University);}public goodStudent(string uv): base(){this.University = uv;Console.WriteLine("unviersity:{0}", uv);}}第一种结果

第二种结果

第三种结果

第四种结果

第五种结果

Base 是子类构造函数中引用父类构造函数