sprintf causing segmantation fault

[Saurabh]

Hi all,

I am working on RedHat Linux GCC 3.0.
I am trying to convert a long to string through sprintf.
but i m getting segmantation fault.
I tried snprintf also but no avail.here is the piece of code..

----------------------------
long myLong=200000;
char myStr[50];
memset[myStr,'\0',50];
sprintf(myStr,"%s",myLong);

-------------------------------------

This sprintf causes segmentation fault.

Hoping for help.

Saurabh

 

[Ian Collins]

Hi all,

I am working on RedHat Linux GCC 3.0.
I am trying to convert a long to string through sprintf.
but i m getting segmantation fault.
I tried snprintf also but no avail.here is the piece of code..

----------------------------
long myLong=200000;
char myStr[50];
memset[myStr,'\0',50];
sprintf(myStr,"%s",myLong);

^
%s is for printing (C style) strings.

use %ld, or use iostreams.

 

[Saurabh]

Hi all,

I am working on RedHat Linux GCC 3.0.
I am trying to convert a long to string through sprintf.
but i m getting segmantation fault.
I tried snprintf also but no avail.here is the piece of code..

----------------------------
long myLong=200000;
char myStr[50];
memset[myStr,'\0',50];
sprintf(myStr,"%s",myLong);

^
%s is for printing (C style) strings.

use %ld, or use iostreams.

hi Ian,
Thanks a lot.
You solved my problem.
actually I thought that the second argument to
sprintf() refers to the format you wish to convert
to,instead it refers to the format you wish to
convert from.
anyways..
thanks again.
saurabh

 

[Geo]

Hi all,

I am working on RedHat Linux GCC 3.0.
I am trying to convert a long to string through sprintf.
but i m getting segmantation fault.
I tried snprintf also but no avail.here is the piece of code..

----------------------------
long myLong=200000;
char myStr[50];
memset[myStr,'\0',50];
sprintf(myStr,"%s",myLong);

^
%s is for printing (C style) strings.

use %ld, or use iostreams.

hi Ian,
Thanks a lot.
You solved my problem.
actually I thought that the second argument to
sprintf() refers to the format you wish to convert
to,instead it refers to the format you wish to
convert from.
anyways..
thanks again.
saurabh

I would suggest that if you are STILL using sprinf, then you haven't
fixed the problem, it will surely break one day. Why not use
boost::lexical_cast (or you're own similar code) instead.

 

[Saurabh]

Saurabh wrote:
Hi all,

I am working on RedHat Linux GCC 3.0.
I am trying to convert a long to string through sprintf.
but i m getting segmantation fault.
I tried snprintf also but no avail.here is the piece of code..

----------------------------
long myLong=200000;
char myStr[50];
memset[myStr,'\0',50];
sprintf(myStr,"%s",myLong);
^
%s is for printing (C style) strings.

use %ld, or use iostreams.

hi Ian,
Thanks a lot.
You solved my problem.
actually I thought that the second argument to
sprintf() refers to the format you wish to convert
to,instead it refers to the format you wish to
convert from.
anyways..
thanks again.
saurabh

I would suggest that if you are STILL using sprinf, then you haven't
fixed the problem, it will surely break one day. Why not use
boost::lexical_cast (or you're own similar code) instead.

hi Geo,
I have never used boost::lexical_cast.Is this an STL component?
or are you hinting me to write my own version of sprintf()?

Thanks & Regards
saurabh

 

[Geo]

Ian Collins wrote:
Saurabh wrote:
Hi all,

I am working on RedHat Linux GCC 3.0.
I am trying to convert a long to string through sprintf.
but i m getting segmantation fault.
I tried snprintf also but no avail.here is the piece of code..

----------------------------
long myLong=200000;
char myStr[50];
memset[myStr,'\0',50];
sprintf(myStr,"%s",myLong);
^
%s is for printing (C style) strings.

use %ld, or use iostreams.

--
Ian Collins.

hi Ian,
Thanks a lot.
You solved my problem.
actually I thought that the second argument to
sprintf() refers to the format you wish to convert
to,instead it refers to the format you wish to
convert from.
anyways..
thanks again.
saurabh

I would suggest that if you are STILL using sprinf, then you haven't
fixed the problem, it will surely break one day. Why not use
boost::lexical_cast (or you're own similar code) instead.

hi Geo,
I have never used boost::lexical_cast.Is this an STL component?
or are you hinting me to write my own version of sprintf()?

Thanks & Regards
saurabh

Hi,

No I was suggesting you write you're own lexical cast function, if you
can't use boost. You could start with something like this, you may want
to make this more robust,

template<typename out, typename in> out lexical_cast(const in &i)
{
std::stringstream ss;
ss << i;
out temp;
ss >> temp;
return temp;
}


then do

int x = 123;
std::string s = lexical_cast<std::string>(x);

you can also do the reverse

std::string s = "5678";
int z = lexical_cast<int>(s);

 

[Old Wolf]

memset[myStr,'\0',50];

Take this line out of your code.

 

[Prawit Chaivong]

memset[myStr,'\0',50];

Take this line out of your code.

Yep, Agree.
And use %d instead of %s.It makes your program think that your 'MyLong'
as a pointer to characters.

 

[Earl Purple]

I have never used boost::lexical_cast.Is this an STL component?
or are you hinting me to write my own version of sprintf()?

Thanks & Regards
saurabh

I would not suggest boost::lexical_cast here. The boost equivalent of
sprintf is boost::format.

lexical_cast is useful for converting the other way, i.e. string to
integer.

 

[Noclambulist]

Saurabh wrote:
Ian Collins wrote:
Saurabh wrote:
Hi all,

I am working on RedHat Linux GCC 3.0.
I am trying to convert a long to string through sprintf.
but i m getting segmantation fault.
I tried snprintf also but no avail.here is the piece of code..

----------------------------
long myLong=200000;
char myStr[50];
memset[myStr,'\0',50];
sprintf(myStr,"%s",myLong);
^
%s is for printing (C style) strings.

use %ld, or use iostreams.

--
Ian Collins.

hi Ian,
Thanks a lot.
You solved my problem.
actually I thought that the second argument to
sprintf() refers to the format you wish to convert
to,instead it refers to the format you wish to
convert from.
anyways..
thanks again.
saurabh


I would suggest that if you are STILL using sprinf, then you haven't
fixed the problem, it will surely break one day. Why not use
boost::lexical_cast (or you're own similar code) instead.

hi Geo,
I have never used boost::lexical_cast.Is this an STL component?
or are you hinting me to write my own version of sprintf()?

Thanks & Regards
saurabh

Hi,

No I was suggesting you write you're own lexical cast function, if you
can't use boost. You could start with something like this, you may want
to make this more robust,

template<typename out, typename in> out lexical_cast(const in &i)
{
std::stringstream ss;
ss << i;
out temp;
ss >> temp;
return temp;
}

but g++ told me that:
In function `out lexical_cast(const in&) [with out = std::string, in =
int]':
instantiated from here
error: `ss' has incomplete type
error: storage size of `ss' isn't known

 

[Marcus Kwok]

No I was suggesting you write you're own lexical cast function, if you
can't use boost. You could start with something like this, you may want
to make this more robust,

template<typename out, typename in> out lexical_cast(const in &i)
{
std::stringstream ss;
ss << i;
out temp;
ss >> temp;
return temp;
}

but g++ told me that:
In function `out lexical_cast(const in&) [with out = std::string, in =
int]':
instantiated from here
error: `ss' has incomplete type
error: storage size of `ss' isn't known

You need #include <sstream> for std::stringstream.