流控制

  1 //using 作为指令，用于为命名空间创建别名或导入其他命名空间中定义的类型,如Class,enum等.
  2 
  3 //using 作为语句，用于定义一个范围，在此范围的末尾(就是}之后)将释放对象
  4 //示例:        
  5 //Font font2 = new Font("Arial", 10.0f);
  6 //using (font2)
  7 //{
  8 //    // use font2
  9 //}
 10 
 11 //using 定义命名空间别名的示例:using MyAlias = MyCompany.Proj.Nested;
 12 using System; //导入其他命名空间中定义的类型
 13 using System.Collections.Generic;
 14 using System.Text;
 15 
 16 namespace ConsoleApplication1 //自定义命名空间
 17 {
 18     class Program
 19     {
 20         static void Main(string[] args)
 21         {
 22             //int a = 10, b = 12; //实例使用当前定义
 23 
 24             //is判断对象是否兼容-----------------
 25             //if (b is object) //is用于判断b是否能兼容object
 26             //{
 27             //    Console.WriteLine("this");
 28             //}
 29 
 30 
 31             //流控制if..else--------------
 32             //if (a < b)
 33             //{
 34             //    Console.WriteLine("true");
 35             //}
 36             //else
 37             //{
 38             //    Confalsole.WriteLine("se");
 39             //}
 40 
 41 
 42             //流控制switch枚举(1)-----------
 43             //switch(a)
 44             //{
 45             //    case 1:
 46             //        Console.WriteLine("1");
 47             //        break;
 48             //    case 10:
 49             //        Console.WriteLine("10");
 50             //        break;
 51             //   default:
 52             //        Console.WriteLine("default");
 53             //        break;
 54             //}
 55             //流控制switch枚举(2)-----------
 56             //string mycountry = Console.ReadLine();
 57             //switch(mycountry)
 58             //{
 59             //    case "china":
 60             //        Console.WriteLine("china");
 61             //        break;
 62             //    case "USA":
 63             //        Console.WriteLine("USA");
 64             //        break;
 65             //    default:
 66             //        Console.WriteLine("no response");
 67             //        break;
 68             //}
 69 
 70 
 71             //流控制while,do while------------
 72             //int i = 0, a = 0;//初始化值
 73             //while(i < 10) //先判断在循环
 74             //{
 75             //    a = a + i;
 76             //    i = i + 1;
 77             //}
 78             //Console.WriteLine(a);
 79 
 80             //do //先执行一次在判断循环条件
 81             //{
 82             //    a = a + i;
 83             //}
 84             //while (i < 10);
 85             //Console.WriteLine(a);
 86             
 87             
 88             //流控制for----------------
 89             //for (int i = 1; i <= 5; i++)
 90             //{
 91             //    Console.WriteLine(i);
 92             //}
 93 
 94  
 95 
 96             //流控制foreach(用于数组)-----------
 97             //int[] ints ={ 1, 2, 3 };
 98             //foreach (int te in ints)
 99             //{
             //    Console.WriteLine(te);
             //}
             
 
            //continue退出循环中的语句(循环迭代)在执行下一迭代,或跳到循环的开头重新循环.
            //break不能用于if之类的非循环流控制,跳出循环.
            //return返回过程中的值给调用者
 
 
             //int[]数组的3种声明方式----------------
             //(1)声明一维数组
             //int[] array1 = new int[5]{ 2, 3, 2, 34, 55 };//定长
             //int[] array1 = new int[]{ 2, 3, 2, 34, 55 };//不定长
             //(2)声明多维数组
             //int[,] array2 = new int[2,2] { { 2, 3}, { 5, 9} };//定长,表示有两组数,每组有两个元素,后面大括号里为数组初始值
             //int[,] array3 = new int[,] { { 2, 3, 44 }, { 5, 9, 45 }, { 32, 43, 23 } };//不定长
             //Console.WriteLine("The array has {0} dinensions", array.Rank);//.Rank返回数组维数
             //int[] array3 ={ 2, 3, 2, 34, 55, 6, 7, 8 };//不用new关键字定义数组
            
             //Lab:遍历出数组中的每个元素------------------------------
             //int[,] array3 = new int[,] { { 2, 3, 44 }, { 5, 9, 45 }, { 32, 43, 23 } };
             //foreach (int i in array3)
             //{
             //    Console.WriteLine("{0}",i);
             //}
 
             //Lab:用Convert.ToDuble获取值,进行数据类型转换后运算出结果------------------------
             //Double r;
             //Console.WriteLine("输入半径求圆周和面积:");
             //r = Convert.ToDouble(Console.ReadLine());//Console.ReadLine()获取的值类型是string,用Convert.ToDouble转换为Double类型
             //Double pi = 3.1416;
             //Double c, s;
             //c = r * r * pi;//求圆面积,在一个运算过程中要使用同一数据类型
             //s = 2 * i;//求圆r * p周长
             //Console.WriteLine("圆的面积是:{0},圆的周长是:{1}", c, s);//大括号里的0,1分别对应后面c,s
 
 
             //类型转换-----------------------------
             //byte a = 1; short b = a; int c = b;
             //long d = c; float e = d; double f = e;
             //int g = 1;
             //short h = (short)g;//强制转换"(类型名) 变量名",注意转换时两个类型不能超范围
             //Console.WriteLine(h.ToString());
 
 
             //Console.WriteLine(20 % 10);       // int  //用20除10,20是10的倍数则没有余数,返回值0,除数和被除数不成倍数返回余数
             //Console.WriteLine(-5 % 2);      // int
             //Console.WriteLine(5.6 % 2.2);   // double
             //Console.WriteLine(5.0m % 2.2m); // decimal,m是C#中的一个合法单位
             //Console.WriteLine(-5.2 % 2.0);  // double
 
 
             //Lab:计算除数是否是被除数的倍数----------------------
             //Int16 a;
             //Console.WriteLine("输入除数:");
             //a = Convert.ToByte(Console.ReadLine());//把获取的值转换为Byte类型
             //Int16 b;
             //Console.WriteLine("输入被除数:");
             //b = Convert.ToByte(Console.ReadLine());
             //if (a % b == 0)//如果a是b的倍数则没有余数,返回值0
             //{
             //    Int16 c = Convert.ToInt16(a / b);
             //    Console.WriteLine("除数{0}是被除数{1}的倍数,结果是{2}.", a, b,c);
             //}
             //else
             //{
             //    Console.WriteLine("除数{0}不是被除数{1}的倍数", a, b);
             //}
 
 
             //Lab:温度转换---------------------
             //String sel;
             //Console.WriteLine("摄氏温度转华氏温度输入1回车,华氏温度转摄氏温度输入2回车.");
             //sel = Console.ReadLine();
             //if (sel != "1" & sel != "2")//过滤不是1和2的数字
             //{
             //    Console.WriteLine("你的输入不正确!");
             //}
             //else
             //{
             //    Int16 select;
             //    select = Convert.ToInt16(sel);
             //    switch (select)
             //    {
             //        case 1:
             //            Console.WriteLine("请输入摄氏温度:");
             //            Single ca1val1, ca1val2;
             //            ca1val1 = Convert.ToSingle(Console.ReadLine());
             //            ca1val2 = Convert.ToSingle(32 + 1.8 * ca1val1);
             //            Console.WriteLine("摄氏温度({0})转换华氏温度值是({1}).", ca1val1, ca1val2);
             //            break;
             //        case 2:
             //            Console.WriteLine("请输入华氏温度:");
             //            Single ca2val1, ca2val2;
             //            ca2val1 = Convert.ToSingle(Console.ReadLine());
             //            ca2val2 = Convert.ToSingle((ca2val1 - 32) * 1.8);
             //            Console.WriteLine("华氏温度({0})转换摄氏温度值是({1}).", ca2val1, ca2val2);
             //            break;
             //        default:
             //            Console.WriteLine("你的输入不正确!");
             //            break;
             //    }
             //}
 
             //增量运算符(++,--)----------------------
             //double x;
             // x = 1.5;
             //Console.WriteLine(++x);//前缀增量,x值为1+x
             //x = 1.5;
             //Console.WriteLine(x++);//后缀增量,x值为x,只有此语句过后x的值才为x+1
             //Console.WriteLine(x);//x值为x+1
 
 
             //Lab:成绩查询------------------------
             //String cj;
             //Console.WriteLine("请输入成绩:");
             //cj = Console.ReadLine();
             //Single tr;
             //try
             //{
             //    tr = Convert.ToSingle(cj);
             //}
             //catch
             //{
             //    Console.WriteLine("你输入了非数字字符");
             //}
             //Single tr2;
             //tr2 = Convert.ToSingle(cj);
             //if (tr2 > 100 & tr2 < 0)
             //{
             //    Console.WriteLine("你的输入{0}不正确,可能大于100或小于0", cj);
             //}
             //else
             //{
             //    Int16 bjg,jg;
             //    bjg = Convert.ToInt16(tr2);
             //    jg = Convert.ToInt16(bjg/10);
             //    switch(jg)
             //    {
             //        case 10:
             //        case 9:
             //            Console.WriteLine("成绩优秀");
             //            break;
             //        case 8:
             //        case 7:
             //            Console.WriteLine("成绩良好");
             //            break;
             //        case 6:
             //            Console.WriteLine("成绩及格");
             //            break;
             //        default:
             //            Console.WriteLine("成绩不及格");
             //            break;
             //    }
             //}
 
 
             //Lab:用while,do,foreach计算1到100之和---------------------------------------------
             //while:
             //Int32 a = 0, i = 1;//int是Int32的别名,数值的默认类型为Int32
             //while (i <= 100)
             //{
             //    a = a + i;
             //    i++;
             //}
             //Console.WriteLine("从1累加到100之和:{0}", a);
 
             //dowhile:
             //do
             //{
             //    a = a + i;
             //    i++;
             //}
             //while (i <= 100);
             //Console.WriteLine("从1累加到100之和:{0}", a);
 
             //for:
             //for (Int32 ifor = 1; ifor <= 100; ifor++)
             //{
             //    a = a + ifor;
             //}
             //Console.WriteLine("从1累加到100之和:{0}", a);
         }
     }
 
     
 }