复习C#得到的启示

            //Console.WriteLine("请输入第一个数：");
            //string s1 = Console.ReadLine();
            //int s2 = Convert.ToInt32(s1);
            //Console.WriteLine("请输入第二个数：");
            //string i1 = Console.ReadLine();
            //int i2 = Convert.ToInt32(i1);
            //Console.WriteLine("{0}+{1}={2}",s2,i2,s2+i2);
            //Console.ReadKey();
            /*Console.WriteLine("请输入年龄：");
            int s1 = Convert.ToInt32(Console.ReadLine());
            if (s1 > 30)
            {
                Console.WriteLine("成年人");
            }
            else
            {
                Console.WriteLine("小孩");
            }
            Console.ReadKey();*/
            //输入密码验证功能
            /*Console.WriteLine("请输入正确的密码：");
            int s1 = Convert.ToInt32(Console.ReadLine());//密码验证出现错误，错误原因1，假设用户输入的为字符串类型那么将出错。2，int类型的范围有限
            if (s1 == 888888)
            {
                Console.WriteLine("密码输入正确");
            }
            else
            {
                Console.WriteLine("密码输入错误");
            }
            Console.ReadKey();*/
            //输入密码验证功能
           /* Console.WriteLine("请输入正确的密码：");
            string s1 = Console.ReadLine();
            if (s1 == "888888")
            {
                Console.WriteLine("密码输入正确");
            }
            else
            {
                Console.WriteLine("密码输入错误");
            }
            Console.ReadKey();*/
            //练习Switch语句
            /*int i = 9;
            switch (i)
            {
                case 1:
                    Console.WriteLine("笨蛋1");
                    break;
                case 2:
                    Console.WriteLine("笨蛋2");
                    break;
                case 9:
                    Console.WriteLine("笨蛋3");
                    break;
                case 3:
                    Console.WriteLine("笨蛋4");
                    break;
                case 4:
                    Console.WriteLine("笨蛋5");
                    break;
                default:
                    Console.WriteLine("你输入的没有意义");
                    break;

            }*/
            //int i = 0;
            //do
            //{
            //    i++;
            //    Console.WriteLine(i);
            //} while (i < -1);
            int i = 0;
            while (i < -1)
            {
                i++;
                Console.WriteLine(i);
            }
            Console.ReadKey();