为什么在我的char *字符串中出现这种讨厌的波浪号〜？

Question

I'm trying to find a file using BFS and recursion , where given a directory and a file , the algorithm needs to check the given directory or all its sub directories .

Now, when I check a directory, sometimes I have an annoying ~ tilde that pops up at the end of the char* string . I've checked with some printf-S and came to a conclusion that the ~ is actually a part of the file-name .

How could that be? Sid I do something wrong?

Here is part of the recursion :

int scanner(char *dirname,char *entries , char * directory , char * file)
{

    struct stat st;


    /* scan the directory and store the entries in a buffer */
   DIR *dir;
   struct dirent *ent;
   int count=1;
   char name[256];

   if ((dir = opendir(dirname)) == NULL)
   {
     perror("Unable to open directory");
     return(0);
   }

   while ((ent = readdir(dir)) != NULL)
       count++;

   rewinddir(dir);

   // here we copy all the file-names from the directory into the buffer
   // we copy all the names using sprintf and strcpy


   while ((ent = readdir(dir)) != NULL)
   {

       strcpy(name,ent->d_name);


       if (strcmp(name , file) == 0 )

       {
           printf("\nFile was found  !!! in first IF\n");
           printf("\n-----------------------------------------------------------------------\n");

           if (stat(name, &st) < 0) {
                perror(name);
                putchar('\n');
                continue;
            }

           printfile(&st , name);
           printf("\nStringer 'name' is : %s" , name);
           printf("\nThe length of %s is %d" , name , strlen(name));
       }

       else // try
       {
           int length = strlen(name);
           char try[length+2];
           strcpy(try,name);
           try[length+1] = '~';
           try[length+2] = '\0';


           printf("\nThe 'name' is : %s" , name);
           printf("\nThe length of %s is %d" , name , strlen(name));
           printf("\nPrint try %s\n" , try);
           if (strcmp(try , file) == 0 )
               printf("\nFile was found  !!! in second IF\n");
       }


       sprintf(entries,"%s",name);
       entries = entries+strlen(name)+1;

       printf("\nStringer name :%s" , name);

       count++;
   }

   if (closedir(dir) != 0)
     perror("Unable to close directory");

     return(count);
}

And from terminal I hit ./exer4 check david.txt , and got :

The 'name' is : ..
The length of .. is 2
Print try ..

Stringer name :..
The 'name' is : .
The length of . is 1
Print try .

Stringer name :.
The 'name' is : insideCheck
The length of insideCheck is 11
Print try insideCheck

Stringer name :insideCheck
The 'name' is : david.txt~
The length of david.txt~ is 10
Print try david.txt~

Stringer name :david.txt~
The 'name' is : doc.txt~
The length of doc.txt~ is 8
Print try doc.txt~

Answer 1

Having a tilde (~) as a suffix means the file is an automatic backup, for instance Emacs tends to create these . Since your example shows tilde-suffixed text ( .txt ) files, it seems very likely that Emacs is the culprit here.

So there's nothing wrong with your code, any tool should show these files since they're actually there.

Answer 2

Are you using vi or Vim as an editor? Those files (whose names end with a ~ ) are temporary files created by vi .