using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace 變量
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("學(xué)習(xí)變量的存儲(chǔ)");
            int a;
            a = 50;                //int為整型變量，不能賦值小數(shù) a=3.14是錯(cuò)誤的
            Console.WriteLine(a);

            Console.ReadKey();
            double b;               //聲明double類(lèi)型數(shù)據(jù)
            b = 3.14;              // 給double類(lèi)型變量賦值
            Console.WriteLine(b);
            Console.ReadKey();
            double d;
            d = 10;
            Console.WriteLine(d); 
            Console.ReadKey();

            String c = "This is a string";   //聲明同時(shí)賦值
            Console.WriteLine(c);
            Console.ReadKey();
            //一次聲明多個(gè)相同類(lèi)型的變量，用逗號(hào)分割
            string aa="Hello ", bb = "The ", cc = "World";
            Console.WriteLine(aa + bb + cc);
            Console.ReadKey();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace changliang
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("學(xué)習(xí)常量的存儲(chǔ)");
            double r = 5;
            const Double pi = 3.14;          //定義常量
            Console.WriteLine("圓的周長(zhǎng)是" + 2 * pi * r);
            Console.WriteLine("圓的面積是" + pi * r*r);
            Console.ReadKey();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace changliang
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("學(xué)習(xí)常量的存儲(chǔ)");
            double r = 5;
            const Double pi = 3.14;          //定義常量
            Console.WriteLine("圓的周長(zhǎng)是" + 2 * pi * r);
            Console.WriteLine("圓的面積是" + pi * r*r);
            Console.Write("輸出完此行后換行嗎？");
            Console.Write("輸出完上面語(yǔ)句后不換行");
            Console.WriteLine();
            Console.Write("輸出完此行后換行嗎？\n");
            Console.Write("輸出完上面語(yǔ)句后換行\(zhòng)n");
            Console.WriteLine();
            Console.Write(@"輸出完此行后換行嗎？\n");      //使用@后，避免轉(zhuǎn)義字符，將會(huì)原樣輸出
            Console.Write("輸出完上面語(yǔ)句后不換行");
            Console.ReadKey();

        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace changliang
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("請(qǐng)輸入您喜歡的水果");
            String friut;
            friut = Console.ReadLine();
            Console.WriteLine("這么巧，我也喜歡吃"+friut);
            Console.Read();

        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace changliang
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("請(qǐng)輸入您的姓名");
            String name;
            name = Console.ReadLine();
            Console.WriteLine("請(qǐng)輸入您的年齡");
            String age = Console.ReadLine(); //用戶與接收用戶輸入，輸入類(lèi)型默認(rèn)為字符串string類(lèi)型
            Console.WriteLine("請(qǐng)輸入您的性別");
            String sex = Console.ReadLine();
            Console.WriteLine("您好："+name+",您的年齡是"+age+"是個(gè)"+sex+"生");
            Console.WriteLine("您好：{0},您的年齡是{1}是個(gè){2}生",name,age,sex);
            Console.Read();

        }
    }
}