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I'm studying regular expressions in c++11 and this regex search is returning false. Does anybody know what I am doing wrong here? . I know that .* stands for any number of characters except newlines.
So i was expecting regex_match() to return true and the output to be "found". However the output is coming out to be "not found".
#include<regex>
#include<iostream>
using namespace std;
int main()
{
bool found = regex_match("<html>",regex("h.*l"));// works for "<.*>"
cout<<(found?"found":"not found");
return 0;
}
835
You need to use a regex_search rather than regex_match:
bool found = regex_search("<html>",regex("h.*l"));
See IDEONE demo
In plain words, regex_search will search for a substring at any position in the given string. regex_match will only return true if the entire input string is matched (same behavior as matches in Java).
The regex_match documentation says:
Returns whether the target sequence matches the regular expression
rgx.
The entire target sequence must match the regular expression for this function >to return true (i.e., without any additional characters before or after the >match). For a function that returns true when the match is only part of the >sequence, seeregex_search.
The regex_search is different:
Returns whether some sub-sequence in the target sequence (the subject) matches the regular expression
rgx(the pattern).
175
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