C / C++ / MFC

Re: strncpy.... [modified]

16-Nov-06 1:27

Hi all,

Is it possible to use the strncpy() function to achive the following:

FileName1.txt to FileName1.abc

I have tried the following:

<code>
int ExtensionLen;
char *ExtensionString;
ExtensionString = FileNameFromClient;
ExtensionLen = strlen(ExtensionString) - 4;
char extstring[20];   
strncpy( (char*)extstring, ExtensionString, ExtensionLen );
strcat((char*)extstring,(char*)".tcp");
</code>

Just to change the extension, or is there something else I could use?

Thanx

The only programmers that are better than C programmers are those who code in 1's and 0's..... Smile | :)

Programm3r

kakan16-Nov-06 2:07

kakan

16-Nov-06 2:07

If you want to do it in plain old C, here is a way:

char fileName[20];
strcpy(fileName, "FileName1.txt");

// Now change extension to ".abc"

// "Smart" coding, assumes there is a dot in the filename
strcpy(strrchr(fileName, '.'), ".txt");

OR (safer):
char * cpDot = strrchr(fileName, '.');
if(NULL != cpDot) strcpy(cpDot, ".txt");

Let the flaming begin! (I won't answer, I have work to do).

-- modified at 8:30 Thursday 16th November, 2006
Thanks, toxcct!

Alcohol. The cause of, and the solution to, all of life's problems - Homer Simpson

toxcct16-Nov-06 2:19

toxcct

16-Nov-06 2:19

this will do if the file name contains only one '.'.

if the file is called for instance foo.test.doc, your code will fail.

You don't know where to start ? ask a good friend

[VisualCalc 3.0][Flags Beginner's Guide]

kakan16-Nov-06 2:33

kakan

16-Nov-06 2:33

Thanks for pointing that out. It's fixed now.

Alcohol. The cause of, and the solution to, all of life's problems - Homer Simpson

Programm3r16-Nov-06 3:03

16-Nov-06 3:03

Thank you toxcct ...

The only programmers that are better than C programmers are those who code in 1's and 0's..... Smile | :)

Programm3r

Programm3r16-Nov-06 3:01

16-Nov-06 3:01

Thank you kakan for the reply, I'll try it. And I don't think this senario will happen:

file1.a.txt

Thanx again

The only programmers that are better than C programmers are those who code in 1's and 0's..... Smile | :)

Programm3r

kakan16-Nov-06 4:21

kakan

16-Nov-06 4:21

Hello.

Anyhow, I've fixed it, when toxcct pointer it out to me.
I changed strchr to strrchr.

Alcohol. The cause of, and the solution to, all of life's problems - Homer Simpson

Re: strncpy [modified]

prasad_som16-Nov-06 2:41

16-Nov-06 2:41

You want to rename file , dont you?
Have you come across this code from MSDN ?

#include <stdio.h>

void main( void )
{
   int  result;
   char old[] = "RENAMER.OBJ", new[] = "RENAMER.JBO";

   /* Attempt to rename file: */
   result = rename( old, new );
   if( result != 0 )
      printf( "Could not rename '%s'\n", old );
   else
      printf( "File '%s' renamed to '%s'\n", old, new );
}

-- modified at 6:34 Friday 17th November, 2006

Hey , come on. Let me know reason before voting me down.

toxcct16-Nov-06 2:58

toxcct

16-Nov-06 2:58

prasad_som wrote:
char new[] = "RENAMER.JBO";

new is a reserved keyword Poke tongue | ;-P

You don't know where to start ? ask a good friend

[VisualCalc 3.0][Flags Beginner's Guide]

prasad_som16-Nov-06 3:01

16-Nov-06 3:01

Its 'c' code Laugh | :laugh:

.

This is header comment from MSDN for posted code,

/* RENAMER.C: This program attempts to rename a file
 * named RENAMER.OBJ to RENAMER.JBO. For this operation
 * to succeed, a file named RENAMER.OBJ must exist and
 * a file named RENAMER.JBO must not exist.
 */

Prasad
Notifier using ATL | Operator new[],delete[][^]

toxcct16-Nov-06 3:09

toxcct

16-Nov-06 3:09

prasad_som wrote:
Its 'c' code

ok, now you say it, but you didn't explain it previously, so i couldn't know.

You don't know where to start ? ask a good friend

[VisualCalc 3.0][Flags Beginner's Guide]

Programm3r16-Nov-06 3:00

16-Nov-06 3:00

Thank you for the reply prasad_som.

Yes, I want to rename the file ... well kinda, the thing is I wrote a tcp/ip client - server. And the client sends a file to the server, but the server must change the extension of the file when the file transfer begins and change it back to the original extension. The thing is all the code is dynamic and file paths & extension can change... tricky .... Smile | :)

Thanx again

The only programmers that are better than C programmers are those who code in 1's and 0's..... Smile | :)

Programm3r

prasad_som16-Nov-06 3:10

16-Nov-06 3:10

hmmm.
You may like to have look at this for parsing file name
basic_string::rfind,CString::ReverseFind. Look to lst '.' character, and change it to rquired.

Prasad
Notifier using ATL | Operator new[],delete[][^]

Programm3r16-Nov-06 3:14

16-Nov-06 3:14

Thank you very much ... I'll check it out... Smile | :)

The only programmers that are better than C programmers are those who code in 1's and 0's..... Smile | :)

Programm3r

David Crow16-Nov-06 4:03

16-Nov-06 4:03

prasad_som wrote:
Look to lst '.' character, and change it to rquired.

Or use PathFindExtension().

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

prasad_som16-Nov-06 18:12

16-Nov-06 18:12

DavidCrow wrote:
Or use PathFindExtension().

Very true. My 5.

Prasad
Notifier using ATL | Operator new[],delete[][^]

David Crow16-Nov-06 4:04

How to read file in reverse order?

16-Nov-06 4:04

« Programm3r » wrote:
Is it possible to use the strncpy() function to achive the following:

FileName1.txt to FileName1.abc

Why not just use PathRenameExtension()?

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

ashokbngr16-Nov-06 1:21

ashokbngr

16-Nov-06 1:21

I wand to read file form end to the start of the file...
byte by byte...
can anyone suggest me or provide me any sample code that helps me...?????? Confused | :confused:

thanks in advance...

Savcejana Sukinobavanthu

Ashok.

Anthony Mushrow16-Nov-06 1:57

Anthony Mushrow

16-Nov-06 1:57

You could do it with a for loop, find the length of the file in bytes (using a while loop or otherwise)

then do a for loop but backwards

for(int i=FileLength; i>=0; i -=1) {

//Read the file i number of bytes

}

David Crow16-Nov-06 3:04

16-Nov-06 3:04

Why do you need to do this? I would suggest reading the file into a buffer, and then reversing that buffer. It'll be much faster this way.

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

Maximilien16-Nov-06 3:46

Maximilien

16-Nov-06 3:46

or reading the file and inserting in the buffer at the beginning instead of at the end.

Maximilien Lincourt
Your Head A Splode - Strong Bad

David Crow16-Nov-06 4:06

16-Nov-06 4:06

Maximilien wrote:
or reading the file and inserting in the buffer at the beginning...

Which is how files are normally read. Confused | :confused:

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb