How to use regex c++?

Question

I've got a problem with c++ regex.
I've got a string like "f 123/123 1234/123/124 12" and I want to get all the numbers before "/".

This is my regexp:

"\s(\d+)".

I tried it on http://rubular.com/ and it works. Here is my code:

std::regex rgx("\\s(\\d+)");
std::smatch match;

if (std::regex_search(line, match, rgx))
{
    std::cout << "Match\n";

    std::string *msg = new std::string();
    std::cout << "match[0]:" << match[0] << "\n";
    std::cout << "match[1]:" << match[1] << "\n";
    std::cout << "match[2]:" << match[2] << "\n";

}

But I get this:

Match
match[0]:123
match[1]:123
match[2]:

I realize that match[0] is not a "groups" like in Python and Ruby.

falsetru · Accepted Answer · 2014-02-09 12:37:40Z

3

regex_search matches once (the first substring that match the regular expression). You need to loop.

Try following:

std::regex rgx("\\s(\\d+)");
std::smatch match;

while (std::regex_search(line, match, rgx))
{
    std::cout << match[0] << std::endl;
    line = match.suffix().str();
}

edited Feb 9, 2014 at 12:37

answered Feb 9, 2014 at 12:30

falsetru

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2 Comments

falsetru Over a year ago

@suspectus, See match_resulsts::suffix and match_resulsts::str.

falsetru Over a year ago

@suspectus, Sorry, I misunderstood. You meant a typo. I fixed it. Thank you for pointing that.

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