Strings in C++

  • Thread starter Thread starter Guest
  • Start date Start date
G

Guest

Well, I have an char* and I need to separe it in pieces... for example I
have this:
"AREA_VERTEX -5.1108 -33.2878 0" and I need to separe this string in an
array of char* with this values...

[0] = "AREA_VERTEX"
[1] = "-5.1108"
[2] = "-33.287"
[3] = "0"

This values are separate by and blank space, please I need any good Idea,
I'm new working with strings in c++

Thnx in advance
 
Well, I have an char* and I need to separe it in pieces... for example I
have this:
"AREA_VERTEX -5.1108 -33.2878 0" and I need to separe this string in an
array of char* with this values...

[0] = "AREA_VERTEX"
[1] = "-5.1108"
[2] = "-33.287"
[3] = "0"

This values are separate by and blank space, please I need any good Idea,
I'm new working with strings in c++
Click to expand...

Hi,

do you want the pointers in your array to point into the oiginal string, or
do they need to point to new buffers?

to split your string is nt so difficult:
you can use std::stringstream for this:

#include <sstream>
#include <iostream>

....

char str[] = "hello world";
std::stringstream test(str);
string str1;
string str2;
test >> str1;
test >> str2;
cout << str1;
cout << '\n';
cout << str2;

this will split your space separated string into substrings.

another way would be to use the std::string class and manually cut your
string in substrings.
that is more work, but you can do this if your string has a very specific
format that is not easy to
parse with stringstream.

--

Kind regards,
Bruno.
(e-mail address removed)
Remove only "_nos_pam"
 
Hector said:
Well, I have an char* and I need to separe it in pieces... for
example I have this:
"AREA_VERTEX -5.1108 -33.2878 0" and I need to separe this string in
an array of char* with this values...

[0] = "AREA_VERTEX"
[1] = "-5.1108"
[2] = "-33.287"
[3] = "0"

This values are separate by and blank space, please I need any good
Idea, I'm new working with strings in c++
Click to expand...

If you're using std::string, here's a simple string splitter (and test
program). This approach is more efficient than using std::stringstream,
with different flexibility tradeoffs. One thing it won't do is skip
consequtive delimitters (e.g. two space) - if there are consequtive
delimitters, you'll get an empty string in the output list.

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

using namespace std;

void split_string(
const string& str,
char delimitter,
vector<string>& ret
)
{
string::size_type delim;
string::size_type prev_delim = 0;

while (string::npos != (delim = str.find_first_of(delimitter,prev_delim)))
{
ret.push_back(str.substr(prev_delim,delim-prev_delim));
prev_delim = delim+1;
}

// Get the tail after the last separator
ret.push_back(str.substr(prev_delim));
}

int main(int argc, char* argv[])
{
if (3 > argc)
{
cerr << "usage: split_test pattern\n";
return 1;
}

vector<string> args;
split_string(argv[1],' ',args);

cout << args.size() << " arguments:\n";
for (vector<string>::iterator it = args.begin(); it != args.end(); ++it)
cout << "'" << *it << "'\n";
}
 
Thanx both of you....

--
"The best way to predict the future, is to invent it"


Carl Daniel said:
Hector said:
Well, I have an char* and I need to separe it in pieces... for
example I have this:
"AREA_VERTEX -5.1108 -33.2878 0" and I need to separe this string in
an array of char* with this values...

[0] = "AREA_VERTEX"
[1] = "-5.1108"
[2] = "-33.287"
[3] = "0"

This values are separate by and blank space, please I need any good
Idea, I'm new working with strings in c++
Click to expand...

If you're using std::string, here's a simple string splitter (and test
program). This approach is more efficient than using std::stringstream,
with different flexibility tradeoffs. One thing it won't do is skip
consequtive delimitters (e.g. two space) - if there are consequtive
delimitters, you'll get an empty string in the output list.

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

using namespace std;

void split_string(
const string& str,
char delimitter,
vector<string>& ret
)
{
string::size_type delim;
string::size_type prev_delim = 0;

while (string::npos != (delim = str.find_first_of(delimitter,prev_delim)))
{
ret.push_back(str.substr(prev_delim,delim-prev_delim));
prev_delim = delim+1;
}

// Get the tail after the last separator
ret.push_back(str.substr(prev_delim));
}

int main(int argc, char* argv[])
{
if (3 > argc)
{
cerr << "usage: split_test pattern\n";
return 1;
}

vector<string> args;
split_string(argv[1],' ',args);

cout << args.size() << " arguments:\n";
for (vector<string>::iterator it = args.begin(); it != args.end(); ++it)
cout << "'" << *it << "'\n";
}
Click to expand...
 
Back
Top