CODEWITHSUNDEEP
c++regex
Don Code
Don Code

Reputation: 878

Complicated regex_match not working in C++

I'm trying to do some input validation for a time in the format

"1:00 to 12:59 and AM/PM"

I created this regex:\b((1[0-2]|0?[1-9]):([0-5][0-9]) *([AaPp][Mm])). I tested it at regexr.com and it worked fine.

However, when I try to do something like:

std::string s ("1:00 AM");
std::regex e ("\b((1[0-2]|0?[1-9]):([0-5][0-9]) *([AaPp][Mm]))");

if (std::regex_match (s,e))
  std::cout << "string object matched\n";

It never works. Any idea what I might be doing wrong?

Upvotes: 2

Views: 166

Answers (2)

Mohammad Yusuf
Mohammad Yusuf

Reputation: 17054

Use a raw string literal R for using single \. You can try like so:

R"(?!0:00|00:00)([0-1]?[0-2]:[0-5]\d\s*[AaPp][Mm])"

(?!0:00|00:00) - Negative look ahead for 0:00 or 00:00 without consuming.

Demo:

https://regex101.com/r/t7Oa0Q/2

Upvotes: 2

Don Code
Don Code

Reputation: 878

Thanks to @MYGz I was able to fix this. Maybe it had something to do with escape characters.

All I did to change @MYGz's suggestion was to remove the \s.

It worked with ([0-1]?[0-2]:[0-5][0-9] *[AaPp][Mm])

Upvotes: 2

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