C++11 正则表达式——实例1

#include <regex>
#include <iostream>
#include <string>
//该实例通过一个函数is_email_valid 来检查一个email地址是否是一个正确的格式。如果格式正确则返回true。

bool is_email_valid(const std::string& email)
{
const std::regex pattern("(\\w+)(\\.|_)?(\\w*)@(\\w+)(\\.(\\w+))+");
return std::regex_match(email, pattern);
}

int main()
{

std::string email1 = "marius.bancila@domain.com";
std::string email2 = "mariusbancila@domain.com";
std::string email3 = "marius_b@domain.co.uk";
std::string email4 = "marius@domain";

std::cout << email1 << " : " << (is_email_valid(email1) ?
"valid" : "invalid") << std::endl;

std::cout << email2 << " : " << (is_email_valid(email2) ?
"valid" : "invalid") << std::endl;

std::cout << email3 << " : " << (is_email_valid(email3) ?
"valid" : "invalid") << std::endl;

std::cout << email4 << " : " << (is_email_valid(email4) ?
"valid" : "invalid") << std::endl;

return 0;

}
/*
marius.bancila@domain.com : valid
mariusbancila@domain.com : valid
marius_b@domain.co.uk : valid
marius@domain : invalid
请按任意键继续. . .
*/