using System;namespace 继承{	public class cat	{		private string _name = null;		private int _age = 0;				public cat(string name,int age)		{			_name = name;			_age = age;			Console.WriteLine();			Console.Write("猫的名字是{0},年龄为{1},",name,age);		}	}	public class mycat:cat//继承自cat类	{		private int _weight;//新增 _weight属性		public mycat(string name,int age,int weight):base(name,age)		{			_weight = weight;			Console.WriteLine("重量为{0}.",_weight);					}	}	class test	{		static void Main()		{			mycat thecat = new mycat("Tom",10,20);		}	}}