7.22

语句分三类：顺序、分支、循环语句

if 嵌套

先规定大的范围再判断小情况

            你能跑过豹子么？接收能或者不能
            Console.Write("你能跑过豹子么？");
            string s = Console.ReadLine();
            if (s == "能")
            {
                Console.WriteLine("你比禽兽还禽兽！！");
            }
            else
            {
                Console.WriteLine("你连禽兽都不如！！");
            }
            Console.ReadLine();

            输入学生姓名，输入考试成绩  double
            若是100,【恭喜你***，满分通过！】
            若是大于等于80小于100，【**,你很优秀，继续保持！】
            若是大于等于60小于80，【**成绩良好】
            大于等于50小于60，【**就差一点点，下次一定要至少及格！】
            小于50，【**你是笨蛋么？】
            Console.Write("请输入您的姓名：");
            string name = Console.ReadLine();
            Console.Write("请输入您的分数：");
            double score = double.Parse(Console.ReadLine());
            if (score >= 0 && score <= 100)
            {
                if (score == 100)
                {
                    Console.WriteLine(name+"，恭喜你，满分通过！");
                }
                else if (score >= 80)
                {
                    Console.WriteLine(name+"，你很优秀！继续保持！");
                }
                else if (score >= 60)
                {
                    Console.WriteLine(name+",成绩良好！");
                }
                else if (score >= 50)
                {
                    Console.WriteLine(name + "，就差一点点！");
                }
                else
                {
                    Console.WriteLine(name+"，你是笨蛋么？");
                }
            }
            else
            {
                Console.WriteLine("输入有误！");
            }

            Console.ReadLine();

多选

  Console.WriteLine("1.汉堡包");
            Console.WriteLine("2.鸡腿");
            Console.WriteLine("3.鸡米花");
            Console.WriteLine("4.鸡肉卷");
            Console.Write("请输入您最想吃的商品的编号：");
            int s = int.Parse(Console.ReadLine());
            switch (s)//括号内是变量名称
            {
                case 1:
                    Console.WriteLine("您选择的是汉堡包！");
                    break;//作用是跳出最近的花括号
                case 2:
                    Console.WriteLine("您选择的是鸡腿！");
                    break;//作用是跳出最近的花括号
                case 3:
                    Console.WriteLine("您选择的是鸡米花！");
                    break;//作用是跳出最近的花括号
                case 4:
                    Console.WriteLine("您选择的是鸡肉卷！");
                    break;//作用是跳出最近的花括号
                default://相当于else（表示以上可能都不是）
                    Console.WriteLine("编号有误，没有此商品！");
                    break;
            }
            Console.ReadLine();

 Console.Write("请输入月份");
            int m = int.Parse(Console.ReadLine());
            int m1 = 31, m2 = 28, m3 = 31, m4 = 30, m5 = 31, m6 = 30, m7 = 31, m8 = 31, m9 = 30, m10 = 31, m11 = 30;
            int d = int.Parse(Console.ReadLine());
            switch (m)
            {
                case 1:
                    Console.WriteLine("第" + d + "天");
                    break;
                case 2:
                    Console.WriteLine("第"+(m1+d)+"天");
                    break;
                case 3:
                    Console .WriteLine("第"+(m1+m2+d)+"天");
                    break;
                case 4:
                    Console.WriteLine("第" + (m1 + m2 + m3 + d) + "天");
                    break;
                case 5:
                    Console.WriteLine("第" + (m1 + m2 + m3 + m4 + d) + "天");
                    break;
                case 6:
                    Console.WriteLine("第" + (m1 + m2 + m3 + m4 + m5 + d) + "天");
                    break;
                case 7:
                    Console.WriteLine("第" + (m1 + m2 + m3 + m4 + m5 +m6+ d) + "天");
                    break;
                case 8:
                    Console.WriteLine("第" + (m1 + m2 + m3 + m4 + m5 +m6+m7+ d) + "天");
                    break;
                case 9:
                    Console.WriteLine("第" + (m1 + m2 + m3 + m4 + m5 + m6 + m7 +m8+ d) + "天");
                    break;
                case 10:
                    Console.WriteLine("第" + (m1 + m2 + m3 + m4 + m5 + m6 + m7 +m8+m9 +d)+"天");
                    break;
                case 11:
                    Console.WriteLine("第" + (m1 + m2 + m3 + m4 + m5 + m6 + m7 + m8 + m9+m10 + d) + "天");
                    break;
                case 12:
                    Console.WriteLine("第" + (m1 + m2 + m3 + m4 + m5 + m6 + m7 + m8 + m9 + m10 +m11+ d) + "天");
                    break;
                default:
                    Console.WriteLine("您的输入有误");
                    break;