小编ger*_*ger的帖子

我已经尝试使用long,并double与c, k, n变量,但NetBeans的显示我一个堆栈溢出错误:

public class Main {

public static void main(String[] args) {
   double c=0; //combinatorial
   double n=5;
   double k=15;

   c= factorial(n)/(factorial(k)*factorial(n-k));

   System.out.print(n+" combinatorial "+k+" between "+c+"\n");

}

    static double factorial (double number) {
        if (number == 0) 
            return 1;
          else 
            return number * factorial(number-1);
   }
}

Exception in thread "main" java.lang.StackOverflowError
    at co.combinatorial.Main.factorial(Main.java:26)
    at co.combinatorial.Main.factorial(Main.java:29)
    at co.combinatorial.Main.factorial(Main.java:29)
    at co.combinatorial.Main.factorial(Main.java:29)
......

Java结果:1

我是否必须使用整数文字或long.parselong

我做错了什么？

我需要将文件从一个目录复制到另一个目录,具体取决于SQL数据库表中是否存在文件名.

为此,我使用以下代码:

using(SqlConnection connection = new SqlConnection("datasource or route"))
{

  connection.Open();

  using(SqlCommand cmd = new SqlCommand("SELECT idPic, namePicFile FROM DocPicFiles", connection))
  using (SqlDataReader reader = cmd.ExecuteReader())
  {

    if (reader != null)
    {
      while (reader.Read())
      {
        //picList IS AN ARRAY THAT Contains All the files names in a directory
        if (picList.Any(s => s.Contains(reader["namePicFile"].ToString())))
        {
          File.Copy("theFile  in the Directory or array picList",  "the destiny directory"+ ".jpg", false)
        }
      }
    }
  }
}

有没有什么办法可以在更短的时间内完成？这需要1小时,为20.876记录.