正则表达式在C ++中不起作用

Question

I am trying to match a regular expression in c++ using regexec .

This is my pattern which i tried was working fine in java

(^.*([0-9]{6}).*([0-9]{9}).*([0-9]{6,7}).*([0-9]{2,3}).*)

I tried this, but getting wrong output

(.*)[[:digit:]{6}](.*)[[:digit:]]{9}(.*)[[:digit:]]{6,7}(.*)[[:digit:]]{2,3}(.*)

Following is my c++ code :

static int compile_regex (regex_t * r, const char * regex_text) {
    int status = regcomp (r, regex_text, REG_EXTENDED|REG_NEWLINE);
    if (status != 0) {
        char error_message[MAX_ERROR_MSG];
        regerror (status, r, error_message, MAX_ERROR_MSG);
        printf ("Regex error compiling '%s': %s\n",
                 regex_text, error_message);
        return 1;
    }
    return 0;
}
static int match_regex (regex_t * r, char * to_match) {
    char * p = to_match;
    int n_matches = 10;
    regmatch_t m[n_matches];
    int i = 0;
    int nomatch = regexec (r, p, n_matches, m, 0);
    return nomatch;
}
int match ( char * find_text ,string regex_txt) {

    char regex_text[regex_txt.size()+1];
    strcpy(regex_text , regex_txt.c_str());
    regex_t r;
    int ret ;
    compile_regex (& r, regex_text);
    ret = match_regex (& r, find_text);
    return ret;
}

Answer 1

There's nothing wrong with POSIX regex, however if you wanted to do this in portable c++11, something like the following will work..

#include <iostream>
#include <regex>

using namespace std;

int main(void) {
    auto str = string("@000172@ 000002000[ 000001@ 13 8");
    auto rx = regex("(^.*([0-9]{6}).*([0-9]{9}).*([0-9]{6,7}).*([0-9]{2,3}).*)");
    auto it = sregex_iterator(str.begin(), str.end(), rx);
    auto ie = sregex_iterator();

    cout << "Found " << distance(it, ie) << " matches\n";
    // print submatches
    for (auto i = it; i != ie; ++i) {
        for(auto s : *i) {
            cout << s << endl;
        }
    }
}

And https://regex101.com/ confirms, that the code is doing the right thing - ie the output looks like this:

Found 1 matches
@000172@ 000002000[ 000001@ 13 8
@000172@ 000002000[ 000001@ 13 8
000172
000002000
000001
13

Answer 2

不要使用与数字也匹配的点，而使用与NON数字匹配的\\D ：

(^\D*([0-9]{6})\D*([0-9]{9})\D*([0-9]{6,7})\D*([0-9]{2,3})\D*)

Answer 3

Check if your compiler is actually supports regex. I had the situation with GCC when it looks like regex are supported (all headers are exists, compilation is OK and so on), but actual result of matching is wrong. Updating GCC to the newer version solved the problem.