Does boost::regex_search support branch sentence like (....)|(....)?

[=?GB2312?B?v63W0A==?=]

#include <iostream>
#include <string>
#include <boost/regex.hpp>
using namespace std;

int main(int argc, char* argv[])
{
string inStr =
"123456"
"abcde"
"1-2";
std::string regstr =
"(\\d+)|"
"(a-z)";
boost::regex _reg(regstr);
boost::smatch what;
std::string::const_iterator _start = inStr.begin();
std::string::const_iterator _end = inStr.end();
while (boost::regex_search(_start, _end, what, _reg))
{
std::string msg1(what[1].first, what[1].second);
cout << msg1.c_str() << endl;
_start = what[1].second;
}
return 0;
}

run result:
123456
1
2

why can't find "abcde"?

[David Harmon]

On Sat, 10 May 2008 19:37:47 -0700 (PDT) in comp.lang.c++, ????
<ke****@gmail.comwrote,

std::string regstr =
"(\\d+)|"
"(a-z)";

>why can't find "abcde"?

Because it doesn't have a '-' or a 'z' in it after the 'a'.

[Jerry Coffin]

In article <46fdda6b-39ad-444b-87b9-
02**********@k1g2000prb.googlegroups.com>, ke****@gmail.com says...

[ ... ]

"(a-z)";

[ ... ]

why can't find "abcde"?

My guess is that you intended to use "[a-z]" instead...

--
Later,
Jerry.

The universe is a figment of its own imagination.

[Jerry Coffin]

In article <MP************************@news.sunsite.dk>,
jc*****@taeus.com says...

In article <46fdda6b-39ad-444b-87b9-
02**********@k1g2000prb.googlegroups.com>, ke****@gmail.com says...

[ ... ]

"(a-z)";

[ ... ]

why can't find "abcde"?

My guess is that you intended to use "[a-z]" instead...

Oops -- to match 'abcde' it'd need to be something like "[a-z]+" -- by
itself, [a-z] only matches a single lower-case letter. To match more
than one, you need to append something like '+' or '*'.

--
Later,
Jerry.

The universe is a figment of its own imagination.

[=?UTF-8?B?RXJpayBXaWtzdHLDtm0=?=]

On 2008-05-11 04:37, 凯ä¸* wrote:

#include <iostream>
#include <string>
#include <boost/regex.hpp>
using namespace std;

int main(int argc, char* argv[])
{
string inStr =
"123456"
"abcde"
"1-2";
std::string regstr =
"(\\d+)|"
"(a-z)";

I think you intended to find a string consisting of either one or more
numbers or one or more lower-case letters. While I'm not familiar with
the Boost::regex dialect the above probably means one or more numbers
followed by a "|" followed by an "a", a "-", and a "z". You probably
want something like this:

((\\d+)|([a-z]+))

Notice that this introduces a new capturing group, there should be a way
to make the added pair of parenthesis non-capturing, probably something
like:

(?:(\\d+)|([a-z]+))

--
Erik Wikström