Re: a simple regexp match using stl algorithms

From:

Howard Hinnant <howard.hinnant@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Wed, 22 Dec 2010 19:00:45 -0800 (PST)

Message-ID:

<273e28c3-6436-44d5-8165-ee58926e5b36@d8g2000yqf.googlegroups.com>

On Dec 22, 6:50 pm, "pers...@googlemail.com" <pers...@gmail.com>
wrote:

Hi,
I have a string. I want to look for the substring that matches
regexp (*).

That is :
string str("abc + (inside brackets)dfsd";

I want to get the substring ---- (inside brackets).

Is it possible using string member functions and algorithms?
How about the same functionality for any vector.

I believe we could use boost.regex. But I am just learning stl algos
thoroughly. I am wondering if there is any nice way using some calls
such as substring, find ,search, adjacent etc.
Thanks

There is nothing in C++03 to help you do this. Boost::regex is a good
library to look to for this functionality. For the next C++ standard
(C++0x), what is now boost::regex has been mostly standardized and is
now std::regex. Here is an example C++0x program:

#include <iostream>
#include <regex>
#include <string>

int
main()
{
    try
    {
        std::string str("abc + (inside brackets)dfsd");
        std::smatch m;
        std::regex_search(str, m, std::regex("\\([^\\)]*\\)"));
        if (m[0].matched)
        {
            std::cout << "Found " << m.str(0) << '\n';
        }
        else
        {
            std::cout << "Not found\n";
        }
    }
    catch (std::exception const& e)
    {
        std::cout << e.what() << '\n';
    }
}

Found (inside brackets)

-Howard