C# 小例子

 1             Console.WriteLine("请输入年份");
 2             try
 3             {
 4                 int year = Convert.ToInt32(Console.ReadLine());
 5                 Console.WriteLine("请输入月份");
 6                 try
 7                 {
 8                     int month = Convert.ToInt32(Console.ReadLine());
 9                     if (month >= 1 && month <= 12)
10                     {
11                         int day = 0;
12                         switch (month)
13                         {
14                             case 1:
15                             case 3:
16                             case 5:
17                             case 7:
18                             case 8:
19                             case 10:
20                             case 12: day = 31; break;
21                             case 2: if ((year % 400 == 0) || (year % 4 == 0 && year % 100 != 0)) day = 29; else day = 28; break;
22                             default: day = 31; break;
23                         }
24                         Console.WriteLine("{0}年{1}月有{2}天", year, month, day);
25                     }
26                     else { Console.WriteLine("输入的月份超出范围"); }
27                 }
28                 catch { Console.WriteLine("输入的月份有误，程序退出"); }
29             }
30             catch { Console.WriteLine("输入的年份有误，程序退出"); }
31             Console.ReadKey();

 1             string strname = "";
 2 
 3             while (strname != "q")
 4             {
 5                 Console.WriteLine("请输入你的姓名，输入q结束");
 6                 strname = Console.ReadLine();
 7             }
 8             Console.ReadKey();
 9             //do...while
10             /*do
11             {
12                 Console.WriteLine("请输入你的姓名，输入q结束");
13                 strname = Console.ReadLine();
14             } while (strname != "q");
15             Console.ReadKey();*/

 1             string input = "";
 2             int max = 0;
 3             while (input != "end")
 4             {
 5                 Console.WriteLine("请输入一个数字，输入end将显示输入数中的最大值");
 6                 input = Console.ReadLine();
 7                 if (input != "end")
 8                 {
 9                     try
10                     {
11                         int number = Convert.ToInt32(input);
12                         if (number > max)
13                         {
14                             max = number;
15                         }
16                     }
17                     catch
18                     {
19                         Console.WriteLine("您收收入的字符串有误，请重新输入");
20                     }
21                 }
22                 else
23                 {
24                     Console.WriteLine("您刚才输入的数字中最大值为{0}", max);
25                 }
26             } Console.ReadKey();

1             for (int i = 1; i <= 9; i++)
2             {
3                 for (int j = 1; j <= i; j++)
4                 {
5                     Console.Write("{0}*{1}={2}\t", i, j, i * j);
6                 } Console.WriteLine();
7             } Console.ReadKey();

 1             int sum = 0;
 2             int i = 1;
 3             while (i <= 100)
 4             {
 5                 if (i % 7 == 0)
 6                 {
 7                     i++;
 8                     continue;
 9                 }
10                 sum += i;
11                 i++;
12             }
13             Console.WriteLine(sum);
14             Console.ReadKey();

 1             for (int i = 2; i <= 100; i++)
 2             {
 3                 bool b = true;//放在两个循环之间，保证变量b为true
 4                 for (int j = 2; j < i; j++)
 5                 {
 6                     //除尽说明不是质数，没有再进行下去的必要
 7                     if (i % j == 0)
 8                     {
 9                         b = false;
10                         break;
11                     }
12                 }
13                 if (b)
14                 {
15                     Console.WriteLine(i);
16                 }
17             } Console.ReadKey();