Changing string

•

What is DaniWeb IT Discussion Community?

You're currently browsing the C section within the Software Development category of DaniWeb, a massive community of 423,281 software developers, web developers, Internet marketers, and tech gurus who are all enthusiastic about making contacts, networking, and learning from each other. In fact, there are 5,273 IT professionals currently interacting right now! Registration is free, only takes a minute and lets you enjoy all of the interactive features of the site.

Join our community!

Please support our C advertiser: Programming Forums

Thread Tools Display Modes

Views: 261 | Replies: 3

•

Join Date: Mar 2008

Posts: 19

Reputation: sjgriffiths is an unknown quantity at this point

Rep Power: 1

Solved Threads: 0

sjgriffiths sjgriffiths is offline

Offline

Newbie Poster

Changing string

Apr 25th, 2008

Hello

I was wondering whether someone could help me with the below

I have a variable called:

char company[50];

I have a string which contains:

"STEPHEN JOHNSON LTD"

I want to change the LTD to LIMITED

How do i do this?

•

Join Date: Sep 2004

Posts: 6,300

Reputation: Narue has much to be proud of

Rep Power: 28

Solved Threads: 455

Narue

Offline

Expert Meanie

Re: Changing string

Apr 25th, 2008

If you know the string is big enough to hold all of the extra characters, it's a relatively simple matter of finding instances of "LTD", shifting everything after the matched substring (to make room), and copying the new substring in:

 Help with Code Tags 
 c Syntax (Toggle Plain Text) 
#include <stdio.h>
#include <string.h>
 
int main ( void )
{
  char company[50] = "STEPHEN JOHNSON LTD";
  char *match = strstr ( company, "LTD" );
 
  if ( match != NULL ) {
    memmove ( match + 7, match + 3, strlen ( match + 3 ) );
    memcpy ( match, "LIMITED", 7 );
 
    puts ( company );
  }
 
  return 0;
}
#include <stdio.h>
#include <string.h>

int main ( void )
{
  char company[50] = "STEPHEN JOHNSON LTD";
  char *match = strstr ( company, "LTD" );

  if ( match != NULL ) {
    memmove ( match + 7, match + 3, strlen ( match + 3 ) );
    memcpy ( match, "LIMITED", 7 );

    puts ( company );
  }

  return 0;
}

I'm a programmer. My attitude starts with arrogance, holds steady at condescension, and ends with hostility. Get used to it.

•

Join Date: Mar 2008

Posts: 19

Reputation: sjgriffiths is an unknown quantity at this point

Rep Power: 1

Solved Threads: 0

sjgriffiths sjgriffiths is offline

Offline

Newbie Poster

Re: Changing string

Apr 25th, 2008

Ha, fantastic Narue...

One more thing. I dont want to change the ltd if its not the end

eg

If i Had

Ltd Stephen Johnson Ltd

I would change this to Ltd Stephen Johnson Limited

Does that make sense?

•

Join Date: Sep 2004

Posts: 6,300

Reputation: Narue has much to be proud of

Rep Power: 28

Solved Threads: 455

Narue

Offline

Expert Meanie

Re: Changing string

Apr 25th, 2008

>Does that make sense?
Absolutely. Unfortunately there's not a standard strrstr function, so the most straightforward solution is to save the previous match until strstr fails. At that point you know you've got the last instance of the substring:

 Help with Code Tags 
 c Syntax (Toggle Plain Text) 
#include <stdio.h>
#include <string.h>
 
int main ( void )
{
  char company[50] = "LTD STEPHEN LTD JOHNSON LTD";
  char *match = company;
  char *last = NULL;
 
  while ( ( match = strstr ( match, "LTD" ) ) != NULL ) {
    last = match;
    match += 3; /* Skip the match so we don't loop forever */
  }
 
  if ( last != NULL ) {
    memmove ( last + 7, last + 3, strlen ( last + 3 ) );
    memcpy ( last, "LIMITED", 7 );
 
    puts ( company );
  }
 
  return 0;
}
#include <stdio.h>
#include <string.h>

int main ( void )
{
  char company[50] = "LTD STEPHEN LTD JOHNSON LTD";
  char *match = company;
  char *last = NULL;

  while ( ( match = strstr ( match, "LTD" ) ) != NULL ) {
    last = match;
    match += 3; /* Skip the match so we don't loop forever */
  }

  if ( last != NULL ) {
    memmove ( last + 7, last + 3, strlen ( last + 3 ) );
    memcpy ( last, "LIMITED", 7 );

    puts ( company );
  }

  return 0;
}

Of course, that might not be a perfect solution if by "not the end" you mean the last word in the string. In that case both the test and replacement are conceptually easier, especially if you don't care about trailing whitespace:

 Help with Code Tags 
 c Syntax (Toggle Plain Text) 
#include <ctype.h>
#include <stdio.h>
#include <string.h>
 
int main ( void )
{
  char company[50] = "LTD STEPHEN LTD JOHNSON LTD";
  size_t i = strlen ( company );
 
  do
    --i;
  while ( isspace ( company[i] ) );
 
  if ( i >= 2 && strncmp ( &company[i - 2], "LTD", 3 ) == 0 )
    strcpy ( &company[i - 2], "LIMITED" );
 
  puts ( company );
 
  return 0;
}
#include <ctype.h>
#include <stdio.h>
#include <string.h>

int main ( void )
{
  char company[50] = "LTD STEPHEN LTD JOHNSON LTD";
  size_t i = strlen ( company );

  do
    --i;
  while ( isspace ( company[i] ) );

  if ( i >= 2 && strncmp ( &company[i - 2], "LTD", 3 ) == 0 )
    strcpy ( &company[i - 2], "LIMITED" );

  puts ( company );

  return 0;
}