More elegant way of removing/ignoring \n

[Marcb]

I'm putting together a small app that reads paths entered line by line in a text file.

I know the issue with reading a variable length line using Fgets and the newline character is as old as the hills but I was wondering if anyone has a more elegant way of dealing with the newline character than my method? :

Fgets(buf,sizeof(buf),*file);
buf[strlen(buf)-1]='\0';

It works but I always think it's too messy and that there must be a better way...

[MrZammler]

That's not bad, but to be complete you should also check for DOS line endings (\r\n) in case those files are edited in a Windows machine.

[Marcb]

That's a good point, these days it would be very likely the file would be edited on a Windows machine, thanks for the tip !

[Piru]

I'm putting together a small app that reads paths entered line by line in a text file.

I know the issue with reading a variable length line using Fgets and the newline character is as old as the hills but I was wondering if anyone has a more elegant way of dealing with the newline character than my method? :

Fgets(buf,sizeof(buf),*file);
buf[strlen(buf)-1]='\0';

It works but I always think it's too messy and that there must be a better way...

One way to handle it is to use sscanf:

Code: [Select]

#include <stdio.h>

int main(void)
{
  char tmp[80], buf[80];
  while (fgets(tmp, sizeof(tmp), stdin))
  {
    if (sscanf(tmp, &quot;%[^\r\n]&quot;, buf) != 1)
    {
      buf[0] = '\0';
    }
    printf(&quot;%s\n&quot;, buf);
  }
  return 0;
}

[Piru]

That's not bad, but to be complete you should also check for DOS line endings (\r\n) in case those files are edited in a Windows machine.

As far as I know all libc implementations on windoze do automagic \r\n -> \n translation when reading file opened in 'text' mode (that is no "b" is appended to the fopen mode. stdin/stdout/stderr are in this mode, too). Also, when writing to filehandle that is in 'text' mode single \n again is translated to \r\n.

Checking for \r doesn't hurt, however.

[Trev]

It should also be noted that the value of '\n' is entirely library-dependent, and '\n' can and should be converted to an environment-specific newline sequence by the library. Technically, a text stream written on system A can't be safely read on system B until a low-level line ending conversion has taken place. Thankfully, the conversion is typically 0x0D0A <-> 0x0A, but you can't take it for granted, particularly when you know the text stream was created on a non-ASCII source system.

As noted, '\n' in the C standard library translates to CR+LF in the text stream in DOS/Windows and LF in AmigaDOS.

EDIT: If you're looking to do strict ASCII conversion or scanning, then "\x0d\x0a" for "\r\n" and "\x0a" for "\n" might be "safer."

Wikipedia's Newline article covers this in pretty good detail.