Copy Part of String Into Other Strings

[sakitah]

Hello Everyone,


Here's the problem (I'm using Visual c++ 6.0):


I have a string:
string1 = "This&is&life";


and i want to use the '&' as a seperator to help me parse this string
into 3 strings so that:


string2 = 'This'
string3 = 'is'
string4 = 'life'


thanx
Peace
Sakitah

 

[Default User]

Hello Everyone,


Here's the problem (I'm using Visual c++ 6.0):


I have a string:
string1 = "This&is&life";

What kind of "string"? A std::string or a C-style array of characters?
The answer tends to be different.



Brian

 

[Mike Wahler]

Hello Everyone,


Here's the problem (I'm using Visual c++ 6.0):


I have a string:
string1 = "This&is&life";


and i want to use the '&' as a seperator to help me parse this string
into 3 strings so that:


string2 = 'This'
string3 = 'is'
string4 = 'life'

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

int main()
{
std::string s1 = "This&is&life";
std::string s2, s3, s4;
std::istringstream iss(s1);

std::getline(iss, s2, '&');
std::getline(iss, s3, '&');
std::getline(iss, s4, '&');

std::cout << s1 << '\n'
<< s2 << '\n'
<< s3 << '\n'
<< s4 << '\n';

return 0;
}

-Mike

 

[Ludy]

Hi Mike,

In case the string is a large one, and we are planning to parse it and
store it in a vector,
how can we get the count of '&' using istringstream so that we can run
a loop to put it in a vector....?
i tired it with string.find but it required the calculation of
positons but its pretty lenghth one.

-Alex

 

[Dan Cernat]

Hi Mike,

In case the string is a large one, and we are planning to parse it and
store it in a vector,
how can we get the count of '&' using istringstream so that we can run
a loop to put it in a vector....?
i tired it with string.find but it required the calculation of
positons but its pretty lenghth one.

-Alex

one doesn't need to count the '&'. Use a std::vector<string> and
push_back your substrings. It will grow by itself.

Dan

 

[Karl Heinz Buchegger]

Hi Mike,

In case the string is a large one, and we are planning to parse it and
store it in a vector,
how can we get the count of '&' using istringstream so that we can run
a loop to put it in a vector....?

An istregstream, as the name suggests, works like a stream. That is,
getline() will tell you when there is nothing more to read:

std::string s2;
std::vector< std::string > words;

while( std::getline( iss, s2, '&' ) )
words.push_back( s2 );

 

[=?iso-8859-1?Q?Ali_=C7ehreli?=]

how can we get the count of '&' using istringstream so that we can run
a loop to put it in a vector....?

You don't need to know the number of elements to fill the vector. Just
push_back:

#include <vector>

/* ... */

std::vector<std::string> sections;

while (iss)
{
std::string section;
std::getline(iss, section, '&');

if (iss)
{
sections.push_back(section);
}
}

i tired it with string.find but it required the calculation of
positons but its pretty lenghth one.

If you really need to know, consider the count_if algorithm.

Ali

 

[sakitah]

Thank You Everyone, I have figured it out. Brian, I was using an
std::string.
Basically, I used find_first_of function to return the first instance
of the '&'
Then I used the append function to place what's at the beginning of the
original string1 until the '&' into string2.
Then I used the erase function to delete from the original string from
0 until the first '&' and so on until I filled the rest of the strings.

Now that I did that, I want to deal with the new strings as integers,
how can I do that?
So, say the originals were:

string1 = "001-202-1234567"

and parsing it into:

string2 = "001";
string3 = "202";
string4 = "1234567";

I want to manipulate these as numbers. Sadly, I cant append from the
original string into an integer, so how can I do it?

Thank You
Sakitah

 

[Karl Heinz Buchegger]

Thank You Everyone, I have figured it out. Brian, I was using an
std::string.
Basically, I used find_first_of function to return the first instance
of the '&'
Then I used the append function to place what's at the beginning of the
original string1 until the '&' into string2.
Then I used the erase function to delete from the original string from
0 until the first '&' and so on until I filled the rest of the strings.

Now that I did that, I want to deal with the new strings as integers,
how can I do that?
So, say the originals were:

string1 = "001-202-1234567"

and parsing it into:

string2 = "001";
string3 = "202";
string4 = "1234567";

I want to manipulate these as numbers. Sadly, I cant append from the
original string into an integer, so how can I do it?

You need to *convert* each string into a number. And again istringstream
does exactly what you want:

int i;
istringstream iss( string1 );
iss > i;

// now i holds the numerical equivalent of the character sequence

As I said in some other posting: istringstream behaves like any other
stream with the only difference that the 'input' comes from a string.

 

[sakitah]

what library do i need to include? (because Im getting an error that
it's an undeclared identifier

 

[Karl Heinz Buchegger]

what library do i need to include? (because Im getting an error that
it's an undeclared identifier

I don't want to get rude, but:

* do you know how to operate the help system that came with your compiler.

* do you have some books to teach you?

* Do you know how to use google for searching information? You have the worlds
knowledge at your finger tips. Use the force, Lucke.

* Just look up an answer Mike gave on a previous question of yours:

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

int main()
{
std::string s1 = "This&is&life";
std::string s2, s3, s4;
std::istringstream iss(s1);

std::getline(iss, s2, '&');
std::getline(iss, s3, '&');
std::getline(iss, s4, '&');

std::cout << s1 << '\n'
<< s2 << '\n'
<< s3 << '\n'
<< s4 << '\n';

return 0;
}

Mike used istringstream and was kind enough to poste a complete program.

 

[sakitah]

If you don't want to get rude, then please don't.
This is afterall one of the resources of the net, and I know the
questions might not seem very complicated for you, but I am under a
very short time limit with my use for the internet. So I try to get as
much as I can. And I do use searches of google and other search
engines.

 

[Marcelo Pinto]

try searching http://www.dinkumware.com/refxcpp.html.

HTH,

Marcelo Pinto

 

[Default User]

what library do i need to include? (because Im getting an error that
it's an undeclared identifier

This is a model for an non-informative post. What error? What
identifier does is say is undefined?

Show the code (a complete, minimal program) along with the exact error
messages. Also read my sig below.


Brian