convert from string to char array

[Gary Wessle]

Hi
I have
char buffer[128] = "jackson";

how can I get the same effect by
string name = "jackson";
char buffer[128] = name; //will not work

I tried
conat_cast<char *(name.c_str()) ;
which fails

thanks

[doug turnbull]

Gary Wessle wrote:

Hi
I have
char buffer[128] = "jackson";

how can I get the same effect by
string name = "jackson";
char buffer[128] = name; //will not work

I tried
conat_cast<char *(name.c_str()) ;
which fails

thanks

Assignment doesn't work with c-strings. C strings are a different
animal from the nice C++ string class. You need to use strcpy, to copy
data from name.c_str() into your buffer. Look here
(http://www.cplusplus.com/ref/cstring/) for more info on functions to
deal with c strings. Also google "c strings" for more info.

[Peter Jansson]

Gary Wessle wrote:

Hi
I have
char buffer[128] = "jackson";

how can I get the same effect by
string name = "jackson";
char buffer[128] = name; //will not work

I tried
conat_cast<char *(name.c_str()) ;
which fails

thanks

Hi,

c_str() returns a conat char* as you probably know. You should perhaps
(re-)consider why you need a char buffer[128].

Sincerely,

Peter Jansson
http://www.p-jansson.com/
http://www.jansson.net/

[Tim Slattery]

Gary Wessle <ph****@yahoo.c omwrote:

>Hi
I have
char buffer[128] = "jackson";

how can I get the same effect by
string name = "jackson";
char buffer[128] = name; //will not work

Sure won't, that tries to assign the address of the string object
named "name" to the char array named "buffer". Nonsensical, probably
won't even compile. If it does compile it will probably get you a
memory protection error of some sort.

You need to copy the contents from one place to another:

strcpy(buffer, name.c_str());

--
Tim Slattery
Sl********@bls. gov

[Default User]

doug turnbull wrote:

>
Gary Wessle wrote:

Hi
I have
char buffer[128] = "jackson";

how can I get the same effect by
string name = "jackson";
char buffer[128] = name; //will not work

I tried
conat_cast<char *(name.c_str()) ;
which fails

thanks

Assignment doesn't work with c-strings. C strings are a different
animal from the nice C++ string class. You need to use strcpy, to copy
data from name.c_str() into your buffer. Look here
(http://www.cplusplus.com/ref/cstring/) for more info on functions to
deal with c strings. Also google "c strings" for more info.

He's not attempting assignment here (which of course doesn't work with
any array type), but rather initialization.

The rules for initializing an array of char include (C99):
[#14] An array of character type may be initialized by a
character string literal, optionally enclosed in braces.
Successive characters of the character string literal
(including the terminating null character if there is room
or if the array is of unknown size) initialize the elements
of the array.
Clearly, the pointer returned by a call to c_str() is not a character
string literal.


Brian

[red floyd]

Tim Slattery wrote:

Gary Wessle <ph****@yahoo.c omwrote:

>Hi
I have
char buffer[128] = "jackson";

how can I get the same effect by
string name = "jackson";
char buffer[128] = name; //will not work

Sure won't, that tries to assign the address of the string object
named "name" to the char array named "buffer". Nonsensical, probably
won't even compile. If it does compile it will probably get you a
memory protection error of some sort.

You need to copy the contents from one place to another:

strcpy(buffer, name.c_str());

--
Tim Slattery
Sl********@bls. gov

Better would be to use a vector<char>.

vector<charbuff er(name.begin() , name.end());
buffer.push_bac k('\0');

You can now access the contiguous data either as a vector, or if you
need to pass it to a legacy API expecting a non-const char*, you can
pass &buffer[0].

[±à³ÌÀË×Ó]

"Gary Wessle дµÀ£º
"

Hi
I have
char buffer[128] = "jackson";

how can I get the same effect by
string name = "jackson";
char buffer[128] = name; //will not work

u can try this :
strncpy(buffer, name , sizeof(buffer)-1);