Question

我正在编写一个列出目录名称的程序。这不是一个非常复杂的代码，但是在启动程序后，我得到了奇怪的错误

df.isnull().sum() * 100 / len(df)

我得到的输出是

#include <dirent.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>


int main() {
    struct dirent * dir;
    struct stat buf;
    DIR *d;
    if(d = opendir("/..."))
    {
        while(dir = readdir(d))
        {
            if(S_ISDIR(buf.st_mode))
                puts(dir->d_name);
            closedir(d);
        }
    }
    else
        perror("read");
return 0;
}

我做错了什么？

Answer 1

    I made a mistake in the code i returned a null value from statiDB class, i didnt intialize List Object, so i modified the code as shown below
    **This complete code below was missing in above question**
```
    in dao class
```
    public class DoctorDao {
        public boolean saveUser(Doctor doc) {
            boolean storedStatus = StaticDB.getDoctorList().add(doc);
            return storedStatus;
        }

    }
```
    In DB class
```
    class StaticDB{
    static List<Doctor> docList=null;

         public static List<Doctor> getDoctorList(){
         Doctor doc1=new Doctor(111,"Shalu","ss@gmail.com");
         Doctor doc2=new Doctor(112,"luke","luke@gmail.com");
         docList=new ArrayList<Doctor>(); //This was missing 
         docList.add(doc1);
         docList.add(doc2);
         return docList;

收件人：

while(dir = readdir(d))
{
    if(S_ISDIR(buf.st_mode))
        puts(dir->d_name);
    closedir(d);
}

这样一来，您就必须先完成操作才能关闭它。

C列出其他目录中目录的名称

1 个答案: