if else、switch、for循环

通过if  else 来做的一个小型简单的国家首都查询  

static void Main(string[] args)
        {

            //国家首都查询

            Console.Write("请输入国家名：");
            string country = Console.ReadLine();
              if (country == "中国")
            {
                Console.WriteLine("中国的首都是北京！");
            }
              else if (country =="日本")
            {
                Console.WriteLine("日本的首都是东京！");
            }
              else if(country =="越南")
            {
                Console.WriteLine("越南的首都是河内！");
            }
             else if (country == "泰国")
            {
                Console.WriteLine("泰国的首都是曼谷!");
            }
             else if (country =="缅甸")
            {
                Console.WriteLine("缅甸的首都是仰光!");
            }
             else
            {
                 Console.WriteLine("请核对后再输入");
             }
              Console.Write("程序结束");
              Console.ReadLine();
        }

 

通过switch循环做了一个简单的小程序

static void Main(string[] args)
        {
            string choice = "1";
            switch (choice)
            {
                case "1":
                    Console.Write("登录");
                    break;
                case "2":
                      Console.Write("注册");
                    break;
                case "3":
                       Console.Write("个人信息");
                    break;

                default:
                    Console.Write("输入错误");
                    break;
            }
            Console.ReadLine();

        }

 

通过for循环和if判断做的一个，判断是否为质数。

static void Main(string[] args)
        {
            Console.Write("请输入一个数：");
            int number = int.Parse(Console.ReadLine());
            int num = 0;
            for (int i = 1; i <= number; i++)
            {
               

                if (number % i == 0)
                {
                    num++;
                }
            }

            if (num == 2)
            {
                Console.Write(number + "是质数");

            }
            else
            {
                Console.WriteLine(number + "不是质数");
            }
            Console.Write("按回车键结束程序");
            Console.ReadLine();
        }

 

同样也是判断是否是质数，这次用的是bool类型判断的

static void Main(string[] args)
        {
            Console.Write("请用户输入一个数：");
            int number = int.Parse(Console.ReadLine());

            bool isFind = false;
            for(int i =2;i <number;i++)
            {
                if( number % i == 0)
                {
                    isFind = true;
                    break;
                }
            }
            if(isFind)
            {
                Console.Write(number+"不是质数");
            }
            else
            {
                Console.WriteLine(number+"是质数");
            }
            Console.Write("按回车键结束程序");
            Console.ReadLine();
        }