pattern search in text strings in c++ - c++

Question

I just want look for a pattern in a string. for example for this "abaxavabaabcabbc" string the app should print "abc" and "abbc". So, the pattern should have "abc" but the numbers of "b" are changing.
pattern => "abc" => the numbers of "b" are changeable.
And the programm should be in c++.

Answer 1

Using regex_search instead of the iterator:
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#include <regex>
#include <string>
#include <iostream>
int main() {
std::regex const pattern("ab+c");
for (std::string const text :
{
"abaxavabaabcabbc",
}) //
{
std::smatch match;
for (auto it = text.cbegin(), e = text.cend();
std::regex_search(it, e, match, pattern); it = match[0].second) {
std::cout << "Match: " << match.str() << "\n";
}
}
}
Prints
Match: abc
Match: abbc

Answer 2

There is only one answer to this question. You MUST use a std::regex. Regular expressions are exactly made for this purpose.
C++ supports also regular expressions. Please see here
The regex "ab+c" will match all strings starting with an "a", having one or more "b" and end with a "c"
See the following very short program:
#include <iostream>
#include <string>
#include <algorithm>
#include <iterator>
#include <regex>
const std::regex re{ R"(ab+c)" };
using Iter = std::sregex_token_iterator;
int main() {
const std::string test{ "abaxavabaabcabbc" };
std::copy(Iter(test.begin(), test.end(), re), Iter(), std::ostream_iterator<std::string>(std::cout, "\n"));
}
This program will iterate over all matched patterns and copy them to std::cout