public class Father
{
        public  int x = 7;
        public void output()
        {
            Console.WriteLine(x);
        }
    }
    public class Son : Father
    {
        int x = 9;
        public void output(int x)
        {
            base.output();
            Console.WriteLine(this.x);
            Console.WriteLine(x);
            Console.WriteLine(base.x);
        }
}
    class Exclass
    {
        public static void Main(string[] args)
        {
            Father obfather = new Father();
            obfather.output();
            Son obson = new Son();
            obson.output(5);
            Console.ReadLine();
        }
    }
以上程序的运行结果是_____________________。（可能有多行）