Right now you're not freeing anything, which is... kind of okay... the same way its okay, if sloppy, to not close open files. It all goes away when the program ends anyway. But if you were doing that 10,000 times in a loop you'd be using 10,000 times as much memory which could definitely be a Bad Thing.
How to free it? As soon as you don't need any of that array anymore, do this:
I have a problem reading characters from keyboard with the scanf function.
Here there is a little piece of code:
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
/* The last 3 libraries are included because in the real program I use some... (4 Replies)
i have a function:
char *pcCityIdToCountryName(ADMIN_DB_DATA *pstHEader, unit uiCityID)
this returns a pointer to CountryName if cityId is given.
to retrieve countryname i give:
char *CountryName;
CountryName = pcCityIdToCountryName(..................);
but when i compile it is giving :... (5 Replies)
i am having a string like
" X1 " ---> string lenght is 30
I have stored this to a chararry . ref
so here ref = " X1 "
now i trim the left space by my function . Si the string now becomes
"X1 " ---> string lenght is 15... (3 Replies)
If one wants to get a start address of a array or a string or a block of memory via a function, there are at least two methods to achieve it:
(1) one is to pass a pointer-to-pointer parameter, like:
int my_malloc(int size, char **pmem)
{
*pmem=(char *)malloc(size);
if(*pmem==NULL)... (11 Replies)
hello all,
my question is not about How code can be rewritten, i just wanna know even though i am not using read only memory of C (i have declared str) why this function gives me segfault :wall:and the other code executes comfortably though both code uses same pointer arithmetic.
... (4 Replies)
Does anyone know?
int x = 1;
int *p = &++x; //ok !
int *q = &x++; //gives an error :O
why the first pointer is ok but the second is an error? (13 Replies)
I'm newbie learner. My all friend use windows just only me use linux.
so i can't solve any problem by myself. i need a solution.
how can i use pointer as a string.
#include<string.h>
#include<stdio.h>
int main()
{
char *s='\0';
gets(s);
puts(s);
return 0;
}
This code work on... (6 Replies)
Hello, I am trying to reverse complement one string and reverse another (NO complement!), both with pointer. My code compiled without error, but did not do the job I wanted.
#include <stdio.h>
#include <stdlib.h>
#include <zlib.h>
#include "kseq.h"
// STEP 1: declare the type of file... (5 Replies)
Discussion started by: yifangt
5 Replies
LEARN ABOUT ULTRIX
sscanf
scanf(3int)scanf(3int)Name
scanf, fscanf, sscanf - convert formatted input
Syntax
#include <stdio.h>
int scanf( format [, pointer ] ... )
char *format;
int fscanf( stream, format [, pointer ] ... )
FILE *stream;
char *format;
int sscanf( s, format [, pointer ] ... )
char *s, *format;
Description
The international functions and are similar to the standard I/O functions. The difference is that the international functions allow you to
use the %digit$ conversion character in place of the I% character you use in the standard I/O functions. The digit is a decimal digit n
from 1 to 9. The international functions apply conversions to the n th argument in the argument list, rather than to the next unused argu-
ment.
You can use % conversion character in the international functions. However, you cannot mix the % conversion character with the %digit$
conversion character in a single call.
In all cases, uses the radix character and collating sequence that is defined by the last successful call to category or If the radix or
collating sequence is undefined, the function uses the C locale definitions.
International Environment
LC_COLLATE Contains the user requirements for language, territory, and codeset for the character collation format. affects the behav-
ior of regular expressions and the string collation functions in If is not defined in the current environment, provides the
necessary default.
LC_NUMERIC If this environment is set and valid, uses the international language database named in the definition to determine radix
character rules.
LANG If this environment variable is set and valid uses the international language database named in the definition to determine
collation and character classification rules. If or is defined, their definitions supersede the definition of LANG.
Examples
The following shows an example of using the function:
scanf("%2$s %1$d", integer, string)
If the input is `` january 9 '', the function assigns 9 to and ``january'' to
Return Values
The function returns the number of successfully matched and assigned input fields. This number can be zero if the function encounters
invalid input characters, as specified by the conversion specification, before it can assign input characters.
If the input ends before the first conflict or conversion, returns EOF. These functions return EOF on end of input and a short count for
missing or invalid data items.
Environment
In POSIX mode, the E, F, and X formats are treated the same as the e, f, and x formats, respectively; otherwise, the upper-case formats
expect double, double, and long arguments, respectively.
See Alsointro(3int), setlocale(3), strtod(3), strtol(3), printf(3int), getc(3s), printf(3s), scanf(3s)
Guide to Developing International Software
scanf(3int)