The Modern C++ Challenge

29. License plate validation

The simplest way to solve this problem is by using regular expressions. The regular expression that meets the described format is "[A-Z]{3}-[A-Z]{2} \d{3,4}".

The first function only has to validate that an input string contains only text that matches this regular expression. For that, we can use std::regex_match(), as follows:

bool validate_license_plate_format(std::string_view str){   std::regex rx(R"([A-Z]{3}-[A-Z]{2} \d{3,4})");   return std::regex_match(str.data(), rx);}int main(){   assert(validate_license_plate_format("ABC-DE 123"));   assert(validate_license_plate_format("ABC-DE 1234"));   assert(!validate_license_plate_format("ABC-DE 12345"));   assert(!validate_license_plate_format("abc-de 1234"));}

The second function ...