How to repeat a user input email if not valid - c++

Question

So I am trying to use a loop in the email setter where if it isn't valid it should repeat the user input email prompt. The thing is, if I type in a valid email at first it will break the loop which is what I want but if I type in an invalid email first it will repeat the loop twice and then if I type in a valid email after that it will still repeat the loop and I'm just stuck in an infinite loop. I know I'm probably doing something stupid but I can't seem to get it working.
User.cpp
#include "pch.h"
#include "User.h"
//Email regex
std::string userEmailRegex = ".+#.+";
//Validates data against a user-defined string
bool validate(std::string regexStr, std::string data)
{
return std::regex_match(data, std::regex(regexStr));
}
User::User()
{
}
User::User(std::string email, std::string password, std::string username)
{
setEmail(email);
setPassword(password);
setUsername(username);
}
User::~User()
{
}
void User::setEmail(std::string email)
{
bool bValid = validate(userEmailRegex, email);
for (;;)
{
if (bValid)
{
this->email = email;
break;
}
else
{
std::cout << "Please enter a valid email adress!\n";
std::cout << "Email: ";
std::cin.clear();
std::cin.ignore(512, '\n');
}
}
}
Main.cpp
#include "pch.h"
#include "User.h"
#include "DkDateTime.h"
User u;
int main()
{
std::cout << "Welcome to MySocialNetwork!\n";
std::cout << "Please Login below:\n";
std::cout << std::endl;
std::vector<User> v;
std::string email;
std::cout << "Email: ";
std::cin >> email;
u.setEmail(email);
std::cout << u.getEmail() << std::endl;
std::cout << std::endl;
}

Answer 1

It looks like you've misplaced your validation code, and inside your setEmail code you never stored the email that the user input
void User::setEmail(std::string email)
{
for (;;)
{
bool bValid = validate(userEmailRegex, email);
if (bValid)
{
this->email = email;
break;
}
else
{
std::cout << "Please enter a valid email adress!\n";
std::cout << "Email: ";
std::cin.clear();
std::cin.ignore(512, '\n');
std::cin >> email;
}
}
}
so if you move bool bValid = validate(userEmailRegex, email); into the loop instead, you should get the expected result.
OBS: not tested but should get you toward the correct validation

Answer 2

You receive an email address as a parameter to a setter method, fine. But then, if it is not valid, you loop asking a new string from stdin, inside the setter method which is at least a questionable design. It will prevent to use that class in a batch context or in a service getting its input from HTTP messages or anything else not tightly bound to a terminal.
For the sake of separation of concerns, the loop should be outside of the user class: it is a UI concern, not user management. IMHO you should make validate a User class static method and move the loop into the main function:
//Validates data against a user-defined string
static bool User::validate(std::string data)
{
//Email regex
static std::string userEmailRegex = ".+#.+";
return std::regex_match(data, std::regex(User::regexStr));
}
void User::setEmail(std::string email, bool validated = false)
{
if (! (validated || validate(userEmailRegex, email))) {
raise std::invalid_argument("Invalid email");
}
this->email = email;
}
int main()
{
...
for (;;) {
std::cout << "Email: ";
std::cin >> email;
if (User::validate(email)) {
u.setEmail(email);
break;
}
else {
std::cout << "Please enter a valid email adress!\n";
}
}
std::cout << u.getEmail() << std::endl;
std::cout << std::endl;
}