how to check if something exists in a struct linked list?
can someone provide an example of a struct linked list, where it has strings as its values, and then how do I check if a specific string (say called buffer) exists in the list of structs?
i dont understand how to make a copy of it to check with
this is what i have
Code:
// CHECK IF ITEM EXISTS IN THE ITEM LIST
check=0; tmp_item_list=item_list;
while(tmp_item_list) {
if (strcmp(tmp_item_list->number,buffer)==0) {
tmp_buffer0[0]='\0';
strcat(tmp_buffer0,tmp_item_list->number);
strcat(tmp_buffer0," ");
strcat(tmp_buffer0,tmp_item_list->name);
strcat(tmp_buffer0," ");
strcat(tmp_buffer0,tmp_item_list->current_price);
strcat(tmp_buffer0,"\n");
send_message(i, tmp_buffer0); check=1; break;
}
tmp_item_list=tmp_item_list->next;
}
i want to make a copy because if i dont then
tmp_item_list=tmp_item_list->next;
will screw it up
also this wont work, because somehow when i iterate through the list, it seems the list repeats again...
this compiles fine with no errors/warnings
---------- Post updated at 10:13 PM ---------- Previous update was at 09:00 PM ----------
Suppose to have:
struct Tstudent
{
string name, surname;
int matriculation_num;
};
struct Tnode
{
Tstudent* student;
Tnodo* next;
} L;I want to deference that "student" pointer. For example, I tried with:
*(L->student).matriculation_numbut it not worked, as terminal... (4 Replies)
i have a linked list set up like
typedef struct client_list {
char *client_name;
int client_socket_fd;
struct client_list *next;
} client;
client *client_list=NULL;
before adding to the list i check if it already exists, only if it does not then i add
if (client_list==NULL... (1 Reply)
Hi,
I have received an application that stores some properties in a file. The existing struct looks like this:
struct TData
{
UINT uSizeIncludingStrings;
// copy of Telnet data struct
UINT uSize;
// basic properties:
TCHAR szHost; //defined in Sshconfig
UINT iPortNr;
TCHAR... (2 Replies)
Hi
#Testing for file existence
if ; then
echo 'SCHOOL data is available for processing'
else
echo 'SCHOOL DATA IS NOT AVAILABLE FOR PROCESSING'
:
i wrote a script, where it begins by checking if file exists or not.
If it exists, it truncates the database... (2 Replies)
Hi guys ,
i got segment fault , and when i trace , found it happens since the value of pointer which is returned by Struct S_client (*ptr) is zero
if (ptr !=0)i know , adding above line of code is not the solution and not correct for the case since above line only check for the pointer... (1 Reply)
Program to reverse a linked list by traversing only once. (1 Reply)
Discussion started by: VSSajjan
1 Replies
LEARN ABOUT MOJAVE
strncat
STRCAT(3) BSD Library Functions Manual STRCAT(3)NAME
strcat, strncat -- concatenate strings
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <string.h>
char *
strcat(char *restrict s1, const char *restrict s2);
char *
strncat(char *restrict s1, const char *restrict s2, size_t n);
DESCRIPTION
The strcat() and strncat() functions append a copy of the null-terminated string s2 to the end of the null-terminated string s1, then add a
terminating ' '. The string s1 must have sufficient space to hold the result.
The strncat() function appends not more than n characters from s2, and then adds a terminating ' '.
The source and destination strings should not overlap, as the behavior is undefined.
RETURN VALUES
The strcat() and strncat() functions return the pointer s1.
SECURITY CONSIDERATIONS
The strcat() function is easily misused in a manner which enables malicious users to arbitrarily change a running program's functionality
through a buffer overflow attack. (See the FSA.)
Avoid using strcat(). Instead, use strncat() or strlcat() and ensure that no more characters are copied to the destination buffer than it
can hold.
Note that strncat() can also be problematic. It may be a security concern for a string to be truncated at all. Since the truncated string
will not be as long as the original, it may refer to a completely different resource and usage of the truncated resource could result in very
incorrect behavior. Example:
void
foo(const char *arbitrary_string)
{
char onstack[8] = "";
#if defined(BAD)
/*
* This first strcat is bad behavior. Do not use strcat!
*/
(void)strcat(onstack, arbitrary_string); /* BAD! */
#elif defined(BETTER)
/*
* The following two lines demonstrate better use of
* strncat().
*/
(void)strncat(onstack, arbitrary_string,
sizeof(onstack) - strlen(onstack) - 1);
#elif defined(BEST)
/*
* These lines are even more robust due to testing for
* truncation.
*/
if (strlen(arbitrary_string) + 1 >
sizeof(onstack) - strlen(onstack))
err(1, "onstack would be truncated");
(void)strncat(onstack, arbitrary_string,
sizeof(onstack) - strlen(onstack) - 1);
#endif
}
SEE ALSO bcopy(3), memccpy(3), memcpy(3), memmove(3), strcpy(3), strlcat(3), strlcpy(3), wcscat(3)STANDARDS
The strcat() and strncat() functions conform to ISO/IEC 9899:1990 (``ISO C90'').
BSD December 1, 2009 BSD
04-04-2011
