C + + Regular expression mailbox

Download library and reference read: http://www.wuzesheng.com/?p=929

Reference: http://blog.csdn.net/wwy851/article/details/6047321

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Use the GNU regular expression library or use the Boost regular expression library.

#include  >iostream> #include  >cstdlib> #include  >string> #include  >regex >  // regular expression  Regular Expression using namespace std;int main  (  ) {    string email_address;    string user_name,  Domain_name;    regex pattern ("([0-9a-za-z\\-_\\.] +) @ ([0-9a-z]+\\. [A-z] {2,3} (\\. [A-z] {2})?);     //  regular expressions, matching rules:    //  group 1th (i.e. user name), matching rules: 0 to 9, A to Z, A to Z, underline, point, Any character in the hyphen     // , repeat over or above     //  middle, an "@" symbol      //  Second group (that is, domain name), matching rules: 0 to 9 or a to Z of any character repeat over or above,    //  next point, Then any character in A to Z repeats 2 to 3 times (such as COM or CN, etc.),    //  a group within the second group, a point, and then any character in A to Z repeats 2 times (such as CN or FR, etc.)      //  inside a whole group repeats 0 or one time     //  input file end character (Windows uses Ctrl+z,unix with Ctrl+d) to end the loop     while  ( cin >> email_address )      {         if  ( regex_match ( email_address, pattern )  )          {             cout <<  "The email address you entered is legal"  << endl;             //  interception of the first group              user_name = regex_replace ( email_address, pattern, string ("$")  );             //  Intercept the second group              domain_name = regex_replace ( email_address,  Pattern, string ("$")  )             cout  <<  "User name:"  << user_name << endl;             cout <<  "domain name:"  << domain_name << endl;             cout << endl;         }        else         {            cout  <<  "The email address you entered is not valid"  << endl << endl;         }    }    return exit_success;}

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C + + Regular expression mailbox