#include <unistd.h>

 #include <stdio.h>

 #include <dirent.h>

 #include <string.h>

 #include <sys/stat.h>

 #include <stdlib.h>

 void printdir(char * dir, int depth)

 {

     DIR * dp = opendir(dir);

     if (NULL == dp)

     {

         fprintf(stderr, "cannot open directory: %s\n", dir);

         return;

     }

     chdir(dir);

     struct dirent * entry;

     struct stat statbuf;

     while ((entry = readdir(dp)) != NULL)

     {

         stat(entry->d_name, &statbuf);

         if (S_ISDIR(statbuf.st_mode))

         {

             if (strcmp(".", entry->d_name) ==  || strcmp("..", entry->d_name) == )

                 continue;

             printf("%*s%s/\n", depth, "", entry->d_name);

             printdir(entry->d_name, depth + );

         }

         else

             printf("%*s%s\n", depth, "", entry->d_name);

         //printf("%*s",4,"*"); 该函数表示输出"___*",前面输出3个空格。

         //如果是printf("%*s",4,"**");则表示输出"__**"，前面输出2个空格。

     }

     chdir("..");

     closedir(dp);

 }

 int main(int argc, char * argv[])

 {

     char * topdir, pwd[] = ".";

     if (argc < )

         topdir = pwd;

     else

         topdir = argv[];

     printf("Directory scan of %s\n", topdir);

     printdir(topdir, );

     printf("done.\n");

     exit();

 }