public static void Main(string[] args)
{
MyDate m1 = new MyDate(24, 3, 2001);
MyDate m2 = new MyDate(24, 3, 2001);
Console.WriteLine(m1.Equals(m2)); //不相等,显示false
m1 = new MyOkDate(24, 3, 2001);
m2 = new MyOkDate(24, 3, 2001);
Console.WriteLine(m1.Equals(m2)); //相等,显示true
}