LinuxQuestions.org - how to check and remove leading zeroes from the buffer using c program

- Programming (https://www.linuxquestions.org/questions/programming-9/)

- - how to check and remove leading zeroes from the buffer using c program (https://www.linuxquestions.org/questions/programming-9/how-to-check-and-remove-leading-zeroes-from-the-buffer-using-c-program-682622/)

amit_pansuria

11-11-2008 09:43 AM

how to check and remove leading zeroes from the buffer using c program

Helo ,
I m writing small module of c.on RHEL 4

I have one buffer (for e.g. buffer = "002"
now I want to check whethere buffer contains leading zeroes and if it contains
leading zeroes then I want to remove all leading zeroes
( i.e. if buffer = "002" then I want to make buffer = "2")

how do I do using c code

Regards,
Amit

tronayne

11-11-2008 10:04 AM

Easy way? Try using strtol() and sprintf(), something like this

Code:

int    value;



/*    get what's in buf as a number    */

value = (int) strtol (buf, (char **) NULL, 10);

/*    copy it back    */

(void) sprintf (buf, "%d", value);

You can also do that all in one whack; replace "value" in the sprintf with the strtol.

You can also use the atoi() function (the strtol() function is more complicated):

Code:

#include <stdio.h>

#include <stdlib.h>



main    ()

{

        char    buf [BUFSIZ];



        (void) sprintf (buf, "002");

        (void) fprintf (stdout, "%d\n", atoi (buf));

}

dwhitney67

11-11-2008 04:32 PM

Another option, is to use strtok().

PHP Code:




  // check if leading zero exists 
  if (buf[0] == '0') 
  { 
    // remove leading zero(es) 
    sprintf(buf, "%s", strtok(buf, "0")); 
  }

Sergei Steshenko

11-11-2008 04:39 PM

Quote:

Originally Posted by dwhitney67 (Post 3338758)

Another option, is to use strtok().

PHP Code:




  // check if leading zero exists 
  if (buf[0] == '0') 
  { 
    // remove leading zero(es) 
    sprintf(buf, "%s", strtok(buf, "0")); 
  }

Well, probably doesn't matter in this case, but 'sprintf' is slow compared to memmove + strlen.

estabroo

11-11-2008 05:31 PM

or something really simple

Code:

        char    buf [BUFSIZ];

        char*  p = buf;

        char*  e = buf+BUFSIZ;

...

        while ((p < e) && (*p == '0') {

          p++;

        }

...

}

All times are GMT -5. The time now is 04:09 PM.