using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication3
{
    class Program
    {
        static void Main(string[] args)
        {

            int a=10;
            double b=10.0;
            string c="hello";
            bool mybool=false;
            mybool = a is int;
            Console.WriteLine("a is int.\t" + mybool);
            mybool = b is double;
            Console.WriteLine("b is double.\t" + mybool);
            mybool = c is string;
            Console.WriteLine("c is string.\t" + mybool);
            Console.ReadKey();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication3
{
    class Program
    {
        static void Main(string[] args)
        {

            Console.WriteLine("请输入你拥有钢笔的数量");
            int qty = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("I have {0} pen{1}.",qty,qty>1?"s":"");
            Console.ReadKey();
        }
    }
}