How to translate (unsigned char []) to string?

[Zhang Liming]

unsigned char rcd[10];

rcd contains 10 chars, such as '1', '2'.... etc.

string str;

the problem is how to pass the contents in rcd to str with minimal cost?

[Jim Langston]

"Zhang Liming" <xp********@gma il.comwrote in message
news:f0******** **@news.yaako.c om...

unsigned char rcd[10];

rcd contains 10 chars, such as '1', '2'.... etc.

string str;

the problem is how to pass the contents in rcd to str with minimal cost?

string str( rcd );
is probably the best way if you can do it.

Otherwise I guess
str = rcd;

is what you need.

[Ian Collins]

Jim Langston wrote:

"Zhang Liming" <xp********@gma il.comwrote in message
news:f0******** **@news.yaako.c om...

>>unsigned char rcd[10];

rcd contains 10 chars, such as '1', '2'.... etc.

string str;

the problem is how to pass the contents in rcd to str with minimal cost?

string str( rcd );
is probably the best way if you can do it.

Otherwise I guess
str = rcd;

is what you need.

Not if rcd is array of *unsigned* char.

If the array is known to be zero terminated, you might be able to get
away with a cast, otherwise you'd have to do something like memcpy to an
array of char and add the terminating '\0'. It all depends what is in
the original array.

--
Ian Collins.

[hamburger]

Yes, you should confirm there is the terminating '\0' at rcd[9] or
before.
Then you can pass (char *)rcd to the string constructor.
On 4ÔÂ23ÈÕ, ÉÏÎç11ʱ44·Ö, Ian Collins <[e-mail] mwrote:

Jim Langston wrote:

"Zhang Liming" <xphenix...@gma il.comwrote in message
news:f0******** **@news.yaako.c om...

>unsigned char rcd[10];

>rcd contains 10 chars, such as '1', '2'.... etc.

>string str;

>the problem is how to pass the contents in rcd to str with minimal cost?

string str( rcd );
is probably the best way if you can do it.

Otherwise I guess
str = rcd;

is what you need.

Not if rcd is array of *unsigned* char.

If the array is known to be zero terminated, you might be able to get
away with a cast, otherwise you'd have to do something like memcpy to an
array of char and add the terminating '\0'. It all depends what is in
the original array.

--
Ian Collins.

[adam.madram]

On Apr 22, 10:07 pm, Zhang Liming <xphenix...@gma il.comwrote:

unsigned char rcd[10];

rcd contains 10 chars, such as '1', '2'.... etc.

string str;

the problem is how to pass the contents in rcd to str with minimal cost?

xphenix.cn.vcf
1KDownload

wouldn't string concatenation would like

str += rcd;

this would just cause it to be appended to the end of str and then you
can just concatenate another '\0'

[Ian Collins]

ad*********@gma il.com wrote:

On Apr 22, 10:07 pm, Zhang Liming <xphenix...@gma il.comwrote:

>>unsigned char rcd[10];

rcd contains 10 chars, such as '1', '2'.... etc.

string str;

the problem is how to pass the contents in rcd to str with minimal cost?

xphenix.cn.v cf
1KDownload

wouldn't string concatenation would like

str += rcd;

this would just cause it to be appended to the end of str and then you
can just concatenate another '\0'

No it wouldn't in this case because rcd is an array of *unsigned* char.

--
Ian Collins.

[James Kanze]

On Apr 23, 5:07 am, Zhang Liming <xphenix...@gma il.comwrote:

unsigned char rcd[10];

rcd contains 10 chars, such as '1', '2'.... etc.

So why is it declared "unsigned char"?

string str;

the problem is how to pass the contents in rcd to str with
minimal cost?

If you know the length, and what to avoid unsightly casts:-),
you can use the two argument template constructor for
std::string:

std::string s( rcd, rcd + N ) ;

Otherwise, reinterpret_cas t can be used:

std::string s( reinterpret_cas t< char const* >( rdc ), N ) ;

, or, if the "string" in rcd is '\0' terminated:

std::string s( reinterpret_cas t< char const* >( rdc ) ) ;

But I think the source of your problem is the original
declaration. The usual convensions are:

characters: char
small integers: signed char
raw memory ("bytes" or bits): unsigned char

--
James Kanze (GABI Software) email:ja******* **@gmail.com
Conseils en informatique orientée objet/
Beratung in objektorientier ter Datenverarbeitu ng
9 place Sémard, 78210 St.-Cyr-l'École, France, [phone]

[Sylvester Hesp]

"Ian Collins" <ia******@hotma il.comwrote in message
news:59******** ******@mid.indi vidual.net...

If the array is known to be zero terminated, you might be able to get
away with a cast, otherwise you'd have to do something like memcpy to an
array of char and add the terminating '\0'. It all depends what is in
the original array.

--
Ian Collins.

The array doesn't need to be zero-terminated:

std::string s(buffer, buffer + 10);
// or
s.assign(buffer , buffer + 10);

- Sylvester Hesp