convert string into an array

[Sudzzz]

Hi,
I'm trying to convert a string something like this
"{201,23,240,56 ,23,45,34,23}" into an array in C++
Please help.
Thanks,
Sudzzz

[Victor Bazarov]

Sudzzz wrote:

I'm trying to convert a string something like this
"{201,23,240,56 ,23,45,34,23}" into an array in C++
Please help.

We're happy to help. What have you done so far and what
are the problems? Read the FAQ, especially section 5.

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

[Sudzzz]

On Jul 3, 3:41 pm, "Victor Bazarov" <v.Abaza...@com Acast.netwrote:

Sudzzz wrote:

I'm trying to convert a string something like this
"{201,23,240,56 ,23,45,34,23}" into an array in C++
Please help.

We're happy to help. What have you done so far and what
are the problems? Read the FAQ, especially section 5.

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

Currently I have a string "{201,23,240,56 ,23,45,34,23}" which changes
frequently (possibly at 3Hz). The numbers can be any number having
less than 4 digits. I want to take this string and place it in an
array so that I can use for certain computational purposes. I've
looked through different possibilities one of which would involve an
extensive string comparison, atoi(), append to array sort of
algorithm. However I realized that when we input arrays c++ accepts it
in the same form as above and then I thought whether I could simulate c
++ input this string when asked for an array.
I don't know where to start.
Thanks,
Sudzzz

http://sudeeppillai.blogspot.com

[Victor Bazarov]

Sudzzz wrote:

On Jul 3, 3:41 pm, "Victor Bazarov" <v.Abaza...@com Acast.netwrote:

>Sudzzz wrote:

>>I'm trying to convert a string something like this
"{201,23,240, 56,23,45,34,23} " into an array in C++
Please help.

We're happy to help. What have you done so far and what
are the problems? Read the FAQ, especially section 5.

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

Currently I have a string "{201,23,240,56 ,23,45,34,23}" which changes
frequently (possibly at 3Hz). The numbers can be any number having
less than 4 digits. I want to take this string and place it in an
array so that I can use for certain computational purposes. I've
looked through different possibilities one of which would involve an
extensive string comparison, atoi(), append to array sort of
algorithm. However I realized that when we input arrays c++ accepts it
in the same form as above and then I thought whether I could simulate
c ++ input this string when asked for an array.

Yes, you can simulate C++ input, and it will involve some character
comparison, atoi (or strtol, more like it), append to array, sort of
algorithm. How do you think the compiler does that?

I don't know where to start.

Start here:

#include <string>
#include <vector>
#include <cassert>

int main() {
std::string mystring("{201, 23,240,56,23,45 ,34,23}");
std::vector<int vint;

// write code to extract numbers from the 'mystring'
// and place them into 'vint'

assert(vint.siz e() == 8);
assert(vint[0] == 201);
assert(vint[1] == 23);
assert(vint[2] == 240);
assert(vint[3] == 56);
assert(vint[4] == 23);
assert(vint[5] == 45);
assert(vint[6] == 34);
assert(vint[7] == 23);
}

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

[Zachary Turner]

On Jul 3, 2:54 pm, Sudzzz <sudeep.um...@g mail.comwrote:

On Jul 3, 3:41 pm, "Victor Bazarov" <v.Abaza...@com Acast.netwrote:

Sudzzz wrote:

I'm trying to convert a string something like this
"{201,23,240,56 ,23,45,34,23}" into an array in C++
Please help.

We're happy to help. What have you done so far and what
are the problems? Read the FAQ, especially section 5.

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

Currently I have a string "{201,23,240,56 ,23,45,34,23}" which changes
frequently (possibly at 3Hz). The numbers can be any number having
less than 4 digits. I want to take this string and place it in an
array so that I can use for certain computational purposes. I've
looked through different possibilities one of which would involve an
extensive string comparison, atoi(), append to array sort of
algorithm. However I realized that when we input arrays c++ accepts it
in the same form as above and then I thought whether I could simulate c
++ input this string when asked for an array.
I don't know where to start.
Thanks,
Sudzzz

http://sudeeppillai.blogspot.com

You will have to tokenize the string, extracting characters between an
open curly brace '{', a comma ',' and a close curly brace '}'.

std::string str_array = "{201,23,240,56 ,23,45,34,23}";
std::string::si ze_type pos = 0;

std::vector<int int_array;

while (pos != std::string::np os)
{
std::string::si ze_type pos2;

pos = str_array.find_ first_not_of("{ ,}", pos);
if (pos == std::string::np os) break;
pos2 = str_array.find_ first_of("{,}", pos);

std::string str_number = str_array.subst r(pos, pos2-pos+1);
int number = atoi(str_number .c_str()); //Might use a stream here
instead
int_array.push_ back(number);

pos2 = pos;
}
I'm sure this will have some off-by-one errors and other bugs, because
I am not familiar with the signature of all these functions from
memory, but the idea is the same.

[Jim Langston]

"Sudzzz" <su**********@g mail.comwrote in message
news:11******** **************@ k29g2000hsd.goo glegroups.com.. .

On Jul 3, 3:41 pm, "Victor Bazarov" <v.Abaza...@com Acast.netwrote:

>Sudzzz wrote:

I'm trying to convert a string something like this
"{201,23,240,56 ,23,45,34,23}" into an array in C++
Please help.

We're happy to help. What have you done so far and what
are the problems? Read the FAQ, especially section 5.

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

Currently I have a string "{201,23,240,56 ,23,45,34,23}" which changes
frequently (possibly at 3Hz). The numbers can be any number having
less than 4 digits. I want to take this string and place it in an
array so that I can use for certain computational purposes. I've
looked through different possibilities one of which would involve an
extensive string comparison, atoi(), append to array sort of
algorithm. However I realized that when we input arrays c++ accepts it
in the same form as above and then I thought whether I could simulate c
++ input this string when asked for an array.
I don't know where to start.

I would use a stringstream. Output of following program is:

201 23 240 56 23 45 34 23

#include <iostream>
#include <sstream>
#include <string>
#include <vector>

int main()
{
std::string str_array = "{201,23,240,56 ,23,45,34,23}";
std::stringstre am Buffer;
Buffer << str_array;
char Trash;
Buffer >Trash; // Throw away (
int Value;
std::vector<int Data;
while ( Buffer >Value )
{
Data.push_back( Value );
Buffer >Trash; // Throw away , or )
}

// Display vector data
for ( std::vector<int >::iterator it = Data.begin(); it != Data.end();
++it )
std::cout << *it << " ";

}

[Marcus Kwok]

Sudzzz <su**********@g mail.comwrote:

I'm trying to convert a string something like this
"{201,23,240,56 ,23,45,34,23}" into an array in C++

Was BobR's answer not satisfactory to you when you asked this a week
ago?

http://groups.google.com/group/comp....50f516682ccbc/

--
Marcus Kwok
Replace 'invalid' with 'net' to reply

[James Kanze]

On Jul 3, 9:54 pm, Sudzzz <sudeep.um...@g mail.comwrote:

On Jul 3, 3:41 pm, "Victor Bazarov" <v.Abaza...@com Acast.netwrote:

Sudzzz wrote:

I'm trying to convert a string something like this
"{201,23,240,56 ,23,45,34,23}" into an array in C++
Please help.

We're happy to help. What have you done so far and what
are the problems? Read the FAQ, especially section 5.

Currently I have a string "{201,23,240,56 ,23,45,34,23}" which changes
frequently (possibly at 3Hz). The numbers can be any number having
less than 4 digits. I want to take this string and place it in an
array so that I can use for certain computational purposes.

Is the number of elements constant, i.e. always 8. If so, use
boost::regex to validate the syntax and break the string down
into 8 substrings with just the numbers. Then use
istringstream, initialized with each of the substrings, to
convert. (This is definitly not the fastest solution, but it
should be adequate for three times a second, and it is certainly
the easiest to write.)

Otherwise, you'll have to write a simple parser yourself. Again,
you'll use istringstream. A couple of hints:

char ch ;
stream >ch ;

gets the next non-blank character. (Attention: the character is
extracted from the stream, and is no longer available.) And

int i ;
stream >i ;

to read an int.

So a priori, something like the following should do the trick:

char ch ;
stream >ch ;
if ( ! stream || ch != '{' ) {
error...
}
do
{
int i ;
stream >i >ch ;
if ( stream ) {
result.push_bac k( i ) ;
}
} while ( stream && ch == ',' ) ;
if ( ! stream || ch != '}' ) {
error ...
}

--
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]

[James Kanze]

On Jul 3, 10:46 pm, "Jim Langston" <tazmas...@rock etmail.comwrote :

I would use a stringstream.

Just curious, but why a stringstream, and not an istringstream?

[...]

std::string str_array = "{201,23,240,56 ,23,45,34,23}";
std::stringstre am Buffer;
Buffer << str_array;

Why those two lines, instead of simply:

std::istringstr eam Buffer( str_array ) ;

char Trash;
Buffer >Trash; // Throw away (

Throw away, or verify, as a syntax check? (In my experience,
you can never verify input too much.)

int Value;
std::vector<int Data;
while ( Buffer >Value )

while ( Buffer >Value && Trash != '}' )

{

And

if ( Trash != (Data.empty() ? '{' : ',') ) {
Buffer.setstate ( std::ios::failb it ) ;
}

here.

Data.push_back( Value );
Buffer >Trash; // Throw away , or )
}

And a final error check:

if ( ! (Buffer >std::ws && Buffer.get() == EOF ) {
error ...
}

// Display vector data
for ( std::vector<int >::iterator it = Data.begin(); it != Data.end();
++it )
std::cout << *it << " ";
}

(But I like your basic algorithm better than the one I
suggested.)

--
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]

[BobR]

James Kanze <ja*********@gm ail.comwrote in message...

/* """

On Jul 3, 10:46 pm, "Jim Langston" <tazmas...@rock etmail.comwrote :

I would use a stringstream.

Just curious, but why a stringstream, and not an istringstream?

[...]

std::string str_array = "{201,23,240,56 ,23,45,34,23}";
std::stringstre am Buffer;
Buffer << str_array;

Why those two lines, instead of simply:

std::istringstr eam Buffer( str_array ) ;

""" */

Aww, c'mon James, we can do better than that. :-}

My original code, revised.
{
std::string stin( "{201,23,240,56 ,23,45,34,23}" );

std::istringstr eam in( stin.substr( 1, stin.size()-2 ) ); // <---- :-}
// assumes the strings are always *that* format, "{....}".

// now use this, or Jim's code from here ( with 'Trash' removed! [1]).
std::vector<int array;
for( std::string line; std::getline( in, line, ',' ); ){
std::istringstr eam conv( line );
int num(0);
conv >num;
if( not conv ){ break;}
array.push_back ( num );
// conv.clear(); conv.str("");
}
for( std::size_t i(0); i < array.size(); ++i ){
std::cout<< array.at( i ) <<" ";
}
}
// output:201 23 240 56 23 45 34 23

[1]
// Buffer >Trash; // Throw away (
char tst = Buffer.peek();
if( tst == '{' || tst == ',' || tst == '}' ){ Buffer.ignore(1 ); }

--
Bob R
POVrookie