int sum = 0;
 int n = int.Parse(Console.ReadLine());
 for (int i = 0; i < n; i++)
 {
      int sum1 = 1;//定义变量sum1，每次循环都赋予其初始值1，求阶乘专用
      for (int j = 1; j <= i+1; j++)
      {
           sum1 = sum1 * j;
      }
      sum = sum + sum1;//将每次阶乘的和相加
 }
 Console.WriteLine(sum);

int count = 0;
for (int qb = 1;qb<50;qb++)
{
     for (int he = 1; he < 20; he++)
     {
            for (int jia = 1; jia < 10; jia++)
            {
                 for (int cai = 1; cai < 7;cai++ )
                 {
                      if (qb * 2 + he * 5 + jia*10+cai*15== 100)
                      {
                           count++;
                           Console.WriteLine("铅笔：{0}，铅笔盒：{1}，文件夹：{2}，彩笔：{3}", qb, he,jia,cai);
                       }
                  }
             }
       }
}
Console.WriteLine(count);    

 1             Console.WriteLine("请输入边长：");
 2             int ii = int.Parse(Console.ReadLine());
 3             Console.WriteLine("打印出来的菱形为：");
 4             //打印上面的三角形
 5             for (int g = 0; g < ii; g++)
 6             {
 7                 
 8                 for (int n = ii - g; n > 1; n--)
 9                 {
10                     Console.Write("  ");
11                 }
12                 for (int m = 1; m <= g; m++)
13                 {
14                     Console.Write(" #");
15                 }
16                
17                 for (int p = 1; p <= g; p++)
18                 {
19                     Console.Write(" #");
20                 }
21                 Console.WriteLine(" #");
22             }
23             //打印下面的三角形
24             for (int j = 0; j < ii - 1; j++)
25             {
26                 for (int a = 1; a <= j + 1; a++)
27                 {
28                     Console.Write("  ");
29                 }
30                 for (int b = ii - j; b > 2; b--)
31                 {
32                     Console.Write(" #");
33                 }
34                 for (int c = ii - j; c > 2; c--)
35                 {
36                     Console.Write(" #");
37                 }
38                 Console.WriteLine(" #");
39             }