HELP!!!! Implement a class that supports all of the basic features of a login se

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HELP!!!! Implement a class that supports all of the basic features of a login server using some premade data structures from the C++ STL: unordered_set and unordered_map.

Today, doing almost anything requires creating an online account and logging into that account. Such accounts store banking information, email, contacts, documents, purchases, medical records, etc. Every entity (a business, government agency, university, etc.) with user accounts must store and maintain this account information on a login server that users can connect to (usually via a webpage) and login (“log in”) to their account with credentials (usually a password). This week, you’ll implement a class that supports all of the basic features of a login server using some premade data structures from the C++ STL: unordered_set and unordered_map.

The following files have been given to you:

1. A C++ header file (loginserver.h) declaring the LoginServer class.

2. A C++ source file (main.cpp) containing a main function with tests.

Create a new C++ source file named loginserver.cpp that implements the class declared in loginserver.h, so that loginserver.cpp and the provided files compile into a program that runs with no failed tests. Submit the source file loginserver.cpp.

//LOGINSERVER.H

#ifndef LOGINSERVER_H

#define LOGINSERVER_H

#include

using namespace std;

class LoginServer

{

public:

// Creates a new server with no accounts.

LoginServer();

// Adds a user to the system with the

// parameter username and password.

// Returns false if the LoginServer already has an

// account with the parameter username. Otherwise returns true.

bool create_user(string username, string password);

// Deletes a user from the system with the specified info.

// Returns true if the parameter information was valid

// (and the user was successfully deleted).

// Otherwise returns false.

bool delete_user(string username, string password);

// Returns the total number of accounts in the system.

int total_user_count();

// Tries to log in a user.

// Returns true if there is a user with this password

// that is not already logged in (i.e. whether login occurred).

// Otherwise returns false.

bool login(string username, string password);

// Tries to log out a user.

// Returns true if a user with this user name was logged in.

// Otherwise returns false.

bool logout(string username);

// Returns true if a user with this name is logged in.

// Otherwise returns false.

bool is_logged_in(string username);

// Returns the number of logged-in users.

int active_user_count();

// Logs out all users.

void logout_everyone();

// Changes a user's password.

// Returns true if there is an account with the parameter

// username and password old_pw (i.e. the password changed).

// Otherwise returns false.

bool change_password(string username, string old_pw, string new_pw);

private:

// Stores the usernames of logged-in users

unordered_set S;

// Stores the mapping from usernames to passwords.

unordered_map M;

};

#endif

//END LOGINSERVER.CPP

//MAIN.H

#include

#include "loginserver.h"

using namespace std;

inline void _test(const char* expression, const char* file, int line)

{

cerr << "test(" << expression << ") failed in file " << file;

cerr << ", line " << line << "." << endl;

abort();

}

#define test(EXPRESSION) ((EXPRESSION) ? (void)0 : _test(#EXPRESSION, __FILE__, __LINE__))

int main()

{

LoginServer ls;

// Test total_user_count(), create_user()

test(ls.create_user("Ernesto", "p455w0rd"));

test(ls.total_user_count() == 1);

test(ls.create_user("Ruby", "QwErTy123"));

test(ls.total_user_count() == 2);

test(ls.create_user("Hugo", "1l0v3c4t5"));

test(ls.total_user_count() == 3);

test(ls.create_user("Margo", "Din0s4ur5!"));

test(ls.total_user_count() == 4);

test(ls.create_user("Berta", "!sc00p0f00d!"));

test(ls.total_user_count() == 5);

test(!ls.create_user("Berta", "anotherp455"));

test(ls.total_user_count() == 5);

test(ls.delete_user("Berta", "!sc00p0f00d!"));

test(ls.total_user_count() == 4);

test(!ls.delete_user("Ernesto", "wrongpassword"));

test(ls.total_user_count() == 4);

test(!ls.delete_user("Ernesto", "Din0s4ur5!"));

test(ls.total_user_count() == 4);

test(!ls.delete_user("Berta", "!sc00p0f00d!"));

test(ls.total_user_count() == 4);

test(ls.create_user("Berta", "!sc00p0f00d!"));

test(ls.total_user_count() == 5);

// Test login(), logout(), is_logged_in()

test(!ls.is_logged_in("Ernesto"));

test(!ls.is_logged_in("Ruby"));

test(!ls.is_logged_in("Hugo"));

test(!ls.is_logged_in("Margo"));

test(!ls.is_logged_in("Berta"));

test(!ls.is_logged_in("Unknown"));

test(ls.login("Ernesto", "p455w0rd"));

test(ls.is_logged_in("Ernesto"));

test(!ls.is_logged_in("Ruby"));

test(!ls.is_logged_in("Hugo"));

test(!ls.is_logged_in("Margo"));

test(!ls.is_logged_in("Berta"));

test(ls.logout("Ernesto"));

test(!ls.is_logged_in("Ernesto"));

test(!ls.is_logged_in("Ruby"));

test(!ls.is_logged_in("Hugo"));

test(!ls.is_logged_in("Margo"));

test(!ls.is_logged_in("Berta"));

test(ls.login("Ruby", "QwErTy123"));

test(ls.login("Hugo", "1l0v3c4t5"));

test(!ls.is_logged_in("Ernesto"));

test(ls.is_logged_in("Ruby"));

test(ls.is_logged_in("Hugo"));

test(!ls.is_logged_in("Margo"));

test(!ls.is_logged_in("Berta"));

test(ls.logout("Ruby"));

test(ls.logout("Hugo"));

test(!ls.is_logged_in("Ernesto"));

test(!ls.is_logged_in("Ruby"));

test(!ls.is_logged_in("Hugo"));

test(!ls.is_logged_in("Margo"));

test(!ls.is_logged_in("Berta"));

test(ls.login("Ruby", "QwErTy123"));

test(ls.login("Berta", "!sc00p0f00d!"));

test(!ls.is_logged_in("Ernesto"));

test(ls.is_logged_in("Ruby"));

test(!ls.is_logged_in("Hugo"));

test(!ls.is_logged_in("Margo"));

test(ls.is_logged_in("Berta"));

// Test logging in with wrong password

test(!ls.login("Margo", "idontknow"));

test(!ls.is_logged_in("Ernesto"));

test(ls.is_logged_in("Ruby"));

test(!ls.is_logged_in("Hugo"));

test(!ls.is_logged_in("Margo"));

test(ls.is_logged_in("Berta"));

// Test logging in when already logged in

test(!ls.login("Ruby", "QwErTy123"));

test(!ls.is_logged_in("Ernesto"));

test(ls.is_logged_in("Ruby"));

test(!ls.is_logged_in("Hugo"));

test(!ls.is_logged_in("Margo"));

test(ls.is_logged_in("Berta"));

// Test logging in a user that doesn't exist

test(!ls.login("Stranger", "Question!"));

test(!ls.is_logged_in("Ernesto"));

test(ls.is_logged_in("Ruby"));

test(!ls.is_logged_in("Hugo"));

test(!ls.is_logged_in("Margo"));

test(ls.is_logged_in("Berta"));

// Test logging out someone not logged in

test(!ls.logout("Hugo"));

test(!ls.is_logged_in("Ernesto"));

test(ls.is_logged_in("Ruby"));

test(!ls.is_logged_in("Hugo"));

test(!ls.is_logged_in("Margo"));

test(ls.is_logged_in("Berta"));

// Test logging out a user that doesn't exist

test(!ls.logout("Stranger"));

test(!ls.is_logged_in("Ernesto"));

test(ls.is_logged_in("Ruby"));

test(!ls.is_logged_in("Hugo"));

test(!ls.is_logged_in("Margo"));

test(ls.is_logged_in("Berta"));

test(ls.logout("Ruby"));

test(ls.logout("Berta"));

test(!ls.is_logged_in("Ernesto"));

test(!ls.is_logged_in("Ruby"));

test(!ls.is_logged_in("Hugo"));

test(!ls.is_logged_in("Margo"));

test(!ls.is_logged_in("Berta"));

// Test active_user_count()

test(ls.active_user_count() == 0);

ls.login("Ernesto", "p455w0rd");

test(ls.active_user_count() == 1);

ls.login("Ruby", "QwErTy123");

test(ls.active_user_count() == 2);

ls.login("Berta", "!sc00p0f00d!");

test(ls.active_user_count() == 3);

ls.login("Berta", "!sc00p0f00d!"); // Already logged in

test(ls.active_user_count() == 3);

ls.login("Berta", "!3x3rc1s3!"); // Wrong password

test(ls.active_user_count() == 3);

ls.login("Stranger", "_Secret_"); // Not a user

test(ls.active_user_count() == 3);

ls.logout("Berto"); // Not a user

test(ls.active_user_count() == 3);

ls.logout("Margo"); // Not logged in

test(ls.active_user_count() == 3);

ls.logout("Berta");

test(ls.active_user_count() == 2);

ls.logout("Ernesto");

test(ls.active_user_count() == 1);

ls.logout("Ruby");

test(ls.active_user_count() == 0);

ls.logout("Berta"); // Not logged in

test(ls.active_user_count() == 0);

// Test logout_everyone()

ls.login("Ernesto", "p455w0rd");

ls.login("Ruby", "QwErTy123");

ls.login("Hugo", "1l0v3c4t5");

ls.login("Margo", "Din0s4ur5!");

ls.login("Berta", "!sc00p0f00d!");

ls.logout_everyone();

test(!ls.is_logged_in("Ernesto"));

test(!ls.is_logged_in("Ruby"));

test(!ls.is_logged_in("Hugo"));

test(!ls.is_logged_in("Margo"));

test(!ls.is_logged_in("Berta"));

test(ls.active_user_count() == 0);

ls.login("Margo", "Din0s4ur5!");

ls.login("Berta", "!sc00p0f00d!");

ls.logout_everyone();

test(!ls.is_logged_in("Ernesto"));

test(!ls.is_logged_in("Ruby"));

test(!ls.is_logged_in("Hugo"));

test(!ls.is_logged_in("Margo"));

test(!ls.is_logged_in("Berta"));

test(ls.active_user_count() == 0);

ls.logout_everyone();

test(!ls.is_logged_in("Ernesto"));

test(!ls.is_logged_in("Ruby"));

test(!ls.is_logged_in("Hugo"));

test(!ls.is_logged_in("Margo"));

test(!ls.is_logged_in("Berta"));

test(ls.active_user_count() == 0);

// Test change_password()

test(ls.login("Ernesto", "p455w0rd"));

ls.logout("Ernesto");

test(!ls.login("Ernesto", "p455w0rd!"));

test(!ls.login("Ernesto", "d1ff3r3nt!"));

ls.change_password("Ernesto", "p455w0rd", "p455w0rd!");

test(!ls.login("Ernesto", "p455w0rd"));

test(ls.login("Ernesto", "p455w0rd!"));

ls.logout("Ernesto");

test(!ls.login("Ernesto", "d1ff3r3nt!"));

ls.change_password("Ernesto", "p455w0rd!", "d1ff3r3nt!");

test(!ls.login("Ernesto", "p455w0rd"));

test(!ls.login("Ernesto", "p455w0rd!"));

test(ls.login("Ernesto", "d1ff3r3nt!"));

ls.logout("Ernesto");

test(!ls.change_password("Ernesto", "wr0ng", "wr0ng2"));

test(!ls.login("Ernesto", "p455w0rd"));

test(!ls.login("Ernesto", "p455w0rd!"));

test(ls.login("Ernesto", "d1ff3r3nt!"));

ls.logout("Ernesto");

test(!ls.change_password("Ernesto", "p455w0rd", "wr0ng2"));

test(!ls.login("Ernesto", "p455w0rd"));

test(!ls.login("Ernesto", "p455w0rd!"));

test(ls.login("Ernesto", "d1ff3r3nt!"));

ls.logout("Ernesto");

// Try to change the password of a user that doesn't exist

test(!ls.change_password("Stranger", "Question!", "Question!2"));

test(!ls.is_logged_in("Stranger"));

test(ls.total_user_count() == 5);

test(!ls.login("Stranger", "Question!"));

test(!ls.login("Stranger", "Question!2"));

// Test delete_user()

test(ls.delete_user("Ernesto", "d1ff3r3nt!"));

test(ls.total_user_count() == 4);

// Try to delete a user by giving the wrong password

test(!ls.delete_user("Ruby", "NoErTy345"));

test(ls.total_user_count() == 4);

test(ls.login("Ruby", "QwErTy123"));

ls.logout("Ruby");

// Try to delete users that don't exist

test(!ls.delete_user("Unknown", "p455w0rd"));

test(ls.total_user_count() == 4);

test(!ls.delete_user("Ernesto", "d1ff3r3nt!"));

test(ls.total_user_count() == 4);

cout << "Assignment complete." << endl;

}

//END MAIN.CPP

Explanation / Answer

loginserver.cpp

#include "loginserver.h"

// Constructor
LoginServer::LoginServer() {
}

// Adds a user to the system with the
// parameter username and password.
// Returns false if the LoginServer already has an
// account with the parameter username. Otherwise returns true.
bool LoginServer::create_user(string username, string password) {
   // emplace returns a pair whose
   // second element is true if emplace is successful
   return M.emplace(username, password).second;
}

// Deletes a user from the system with the specified info.
// Returns true if the parameter information was valid
// (and the user was successfully deleted).
// Otherwise returns false.
bool LoginServer::delete_user(string username, string password) {
// Search for the key username
unordered_map<string, string>::const_iterator it = M.find(username);

   // If key present
   if (it != M.end()) {
       // If password correct
       if (it->second == password) {
           M.erase(username);
           return true;
       }
   }

return false;
}

// Returns the total number of accounts in the system.
int LoginServer::total_user_count() {
return M.size();
}

// Tries to log in a user.
// Returns true if there is a user with this password
// that is not already logged in (i.e. whether login occurred).
// Otherwise returns false.
bool LoginServer::login(string username, string password){
// Search for the key username in the map
unordered_map<string, string>::const_iterator it = M.find(username);

   // If key present
   if (it != M.end()) {
       // If password correct
       if (it->second == password) {
           // emplace returns a pair whose
           // second element is true if emplace is successful
           return S.emplace(username).second;
       }
   }

return false;
}

// Tries to log out a user.
// Returns true if a user with this user name was logged in.
// Otherwise returns false.
bool LoginServer::logout(string username){
// Search for the username in the set
unordered_set<string>::const_iterator it = S.find(username);

   // If username present
   if (it != S.end()) {
       S.erase(username);
       return true;
   }

return false;
}

// Returns true if a user with this name is logged in.
// Otherwise returns false.
bool LoginServer::is_logged_in(string username) {
// Search for the username in the set
unordered_set<string>::const_iterator it = S.find(username);

   // If username present
   if (it != S.end()) {
       return true;
   }

return false;
}

// Returns the number of logged-in users.
int LoginServer::active_user_count() {
return S.size();
}

// Logs out all users.
void LoginServer::logout_everyone() {
S.clear();
}

// Changes a user's password.
// Returns true if there is an account with the parameter
// username and password old_pw (i.e. the password changed).
// Otherwise returns false.
bool LoginServer::change_password(string username, string old_pw, string new_pw) {
// Search for the key username in the map
unordered_map<string, string>::const_iterator it = M.find(username);

   // If key present
   if (it != M.end()) {
       // If old password correct
       if (it->second == old_pw) {
           M[username] = new_pw;
           return true;
       }
   }

return false;
}

Output on running main.cpp
Assignment complete.

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