This is my submission for my Study.com C++ Assignment, Bryan Paronto , 2023-01-21

main.cpp

/**
 *  Study.com - Computer Sciece 102: Intro to C++ Coding Assignment
 *  Author: Bryan Paronto
 *  Date: 2023-01-21
 *
 *  The below is an implementation of a simple Employeee Management System.
 *
 *  To try it out, I've hardcoded 1 user of each permission level. Login with the information below:
 *
 *             Username   Password
 *  Employee-  bryan      bryan
 *  HR      -  susan      susan
 *  Manager - manager     manager
 *
 *  Compilation: I've compiled the following program with the command below:
 *  >  g++ employee-mgmt ./main.cpp -lstdc++
 *
 *  It can then be ran by running `./employee-mgmt` in the command-line in any POSIX-compliant shell.
 *
 * */
#include <cctype>
#include <cstdlib>
#include <iostream>
#include <string>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <functional>

using namespace std;


/*
** Function Declarations
 */
int generateUserId();
void LOG();
void showMainScreen();
void showLoginScreen();
void showMenuScreen();
bool validateLogin();


static bool isLoggedIn = false;

/*
 * Utilities
 **/

// Generate dummy user IDs for demo purposes.
int generateUserId() {
    static int userId = 0;
    return userId++;
}

void LOG(string value){
    cout << "debug > " << value << endl;
}


/*
 * Class Definitions
 **/

// Employee Base class 
// - used for generic employees and as a Base class for employees with higher priveledges
class Employee {
   public:
    string userName;
    string password;
    string name;
    string jobTitle;
    int userId;
    // Constructor, with an optinal userId field.
    Employee(string userName, string name, string password, string jobTitle, int userId = generateUserId()){
        this->userName = userName;
        this->name = name;
        this->password = password;
        this->jobTitle = jobTitle;
        this->userId = userId;
    }
    // Displays menu for regular employees. Default actions and View Record and Quit to Login.
    virtual void displayMenu() {
        cout << "MENU OPTIONS: " << endl;
        cout << "(a) View Employee Record" << endl;
        cout << "(q) Quit to Login Screen" << endl;
        char choice;
        while(true) {
            cout  << "> ";
            cin >> choice;
            switch (choice) {
                case 'a':
                    this->showOwnRecord();
                    break;
                case 'q':
                    this->quitToLoginScreen();
                    break;
                default:
                    cout << "Oops, invalid choice. Try again. " << endl;
                    cout << "You picked: " << choice << endl;
                    break;
            }
        }
    }
    virtual void showOwnRecord() {
        cout << "------------" << endl;
        cout << "EMPLOYEE RECORD" << endl;
        cout << left << setw(12) << "NAME: " << this->name << endl;
        cout << left << setw(12) << "JOB TITLE: " << this->jobTitle << endl;
        cout << left << setw(12) << "USERNAME" << this->userName << endl;
        cout << "------------" << endl;
        cout << endl;
        displayMenu();
    }
    void quitToLoginScreen() {
        cin.clear();
        cin.ignore(1000, '\n');
        cout << "Goodbye.";
        cout << endl;
        isLoggedIn = false;
        showLoginScreen();
    }
};

// A simple data wrapper to help us manager our Employee data in an abstracted manner.
class EmployeeDatabase {
   private:
    // Because our vector consists of differenct classes, we've wrapper it in a reference_wrapper, which allowed this functionality without object slicing.
    vector<reference_wrapper<Employee>> employees;
   public:
    void addEmployee(Employee &employee) {
        this->employees.push_back(employee);
    }
    vector<reference_wrapper<Employee>> getAllEmployees() {
        return this->employees;
    }
    void removeEmployee(int id) {
        // Employee a lamda function to assist with filtering for a matching employee by employee's userId.
        auto it = find_if(employees.begin(), employees.end(), [&](reference_wrapper<Employee> employee) { return employee.get().userId == id; });
        if ( it != employees.end() ) {
            employees.erase(it);
        }
    }
};


// Instantiation of our Employee Database
static EmployeeDatabase db;
// Instantiation of a placeholder for our currenrtly logged in user.
static reference_wrapper<Employee> loggedInUser = *new Employee("", "", "" , "");

// A Manager Employeee class which has extended permissions to view all Employeee Records.
class Manager: public Employee {
   using Employee::Employee;
   public:
    void displayMenu() override {
        cout << "MENU OPTIONS: " << endl;
        cout << "(a) View Employee Record" << endl;
        cout << "(b) View All Employee Records" << endl;
        cout << "(q) Quit to Login Screen" << endl;
        char choice;
        while(true) {
            cout  << "> ";
            cin >> choice;
            switch (choice) {
                case 'a':
                    this->showOwnRecord();
                    break;
                case 'b':
                    this->showSearchAndViewRecordScreen();
                    break;
                case 'q':
                    this->quitToLoginScreen();
                    break;
                default:
                    cout << "Oops, invalid choice. Try again. " << endl;
                    cout << "You picked: " << choice << endl;
                    break;
            }
        }
    }
    // View a list of all employee records as well as the individual details of each record.
    void showSearchAndViewRecordScreen() {
        cout << "------------" << endl;
        cout << "ALL EMPLOYEE RECORDS" << endl;
        cout << left << setw(6) << "ID" << setw(15) << "NAME" << setw(10) << "JOB TITLE" << endl;
        for (const auto& employee : db.getAllEmployees()) {
            string formattedId = "(" + to_string(employee.get().userId) + ")";
            cout << left << setw(6) << formattedId;
            cout << setw(15) << employee.get().name << setw(10) << employee.get().jobTitle << endl;
        }
        cout << endl;
        cout << "------------" << endl;
        cout  << "Enter User ID to view Employee Record. Press q to quit to login screen." << endl;
        string employeeChoice;
        while(true) {
            cout  << "> ";
            cin >> employeeChoice;
            if (employeeChoice == "q") {
                this->quitToLoginScreen();
            }
            for (const auto& employee : db.getAllEmployees()) {
                if (to_string(employee.get().userId) == employeeChoice) {
                    cout << "------------" << endl;
                    cout << "EMPLOYEE RECORD" << endl;
                    cout << left << setw(12) << "NAME: " << employee.get().name << endl;
                    cout << left << setw(12) << "JOB TITLE: " << employee.get().jobTitle << endl;
                    cout << left << setw(12) << "USERNAME" << employee.get().userName << endl;
                    cout << "------------" << endl;
                    cout << endl;
                    break;
                }
            }
          showSearchAndViewRecordScreen();
        }
    }
};

// A HumanResourcesEmployee Class, with extended permissions to allow for C.R.U.D (Create, Read, Update, Delete) of employee objects.
class HumanResourcesEmployee: public Employee {
   using Employee::Employee;
   public:
    void displayMenu() override {
        cout << "MENU OPTIONS: " << endl;
        cout << "(a) View Employee Record" << endl;
        cout << "(b) View All Employee Records" << endl;
        cout << "(c) Add New Employee Record " << endl;
        cout << "(d) Delete Employee Record" << endl;
        cout << "(e) Edit Employee Record" << endl;
        cout << "(q) Quit to Login Screen" << endl;
        char choice;
        while(true) {
            cout  << "> ";
            cin >> choice;
            switch (choice) {
                case 'a':
                    this->showOwnRecord();
                    break;
                case 'b':
                    this->showSearchAndViewRecordScreen();
                    break;
                case 'c':
                    this->addRecordScreen();
                    break;
                case 'd':
                    this->deleteRecordScreen();
                    break;
                case 'e':
                    this->editRecordScreen();
                    break;
                case 'q':
                    this->quitToLoginScreen();
                    break;
                default:
                    cout << "Oops, invalid choice. Try again. " << endl;
                    cout << "You picked: " << choice << endl;
                    break;
            }
        }
    }
    void showSearchAndViewRecordScreen() {
        cout << "------------" << endl;
        cout << "ALL EMPLOYEE RECORDS" << endl;
        cout << left << setw(6) << "ID" << setw(15) << "NAME" << setw(10) << "JOB TITLE" << endl;
        for (const auto& employee : db.getAllEmployees()) {
            string formattedId = "(" + to_string(employee.get().userId) + ")";
            cout << left << setw(6) << formattedId;
            cout << setw(15) << employee.get().name << setw(10) << employee.get().jobTitle << endl;
        }
        cout << endl;
        cout << "------------" << endl;
        cout  << "Enter User ID to view Employee Record. Press m to go back to Menu. Press q to quit to login screen." << endl;
        string employeeChoice;
        while(true) {
            cout  << "> ";
            cin >> employeeChoice;
            if (employeeChoice == "q") {
                this->quitToLoginScreen();
            }
            if (employeeChoice == "m") {
                this->displayMenu();
            }
            for (const auto& employee : db.getAllEmployees()) {
                if (to_string(employee.get().userId) == employeeChoice) {
                    cout << "------------" << endl;
                    cout << "EMPLOYEE RECORD" << endl;
                    cout << left << setw(12) << "NAME: " << employee.get().name << endl;
                    cout << left << setw(12) << "JOB TITLE: " << employee.get().jobTitle << endl;
                    cout << left << setw(12) << "USERNAME" << employee.get().userName << endl;
                    cout << "------------" << endl;
                    cout << endl;
                    break;
                }
            }
          showSearchAndViewRecordScreen();
        }
    }
    void addRecordScreen() {
      string newName, newJobTitle, newUserName, newPassword;
      cout << "ADD EMPLOYEE RECORD" << endl;
      cout << "Enter new user's name: ";
      cin.ignore();
      getline(cin, newName);
      cout << "Enter user's Job Title: ";
      getline(cin, newJobTitle);
      cout << "Enter user's username: ";
      getline(cin, newUserName);
      cout << "Enter user's password: ";
      getline(cin, newPassword);
      if (cin.fail()) {
          cin.clear();
          cin.ignore(1000, '\n');
      } else {
        Employee newEmployee(newUserName, newName, newPassword, newJobTitle);
        db.addEmployee(newEmployee);
        cout << "Saved New Employee." << endl;
        this->displayMenu();
      }
    }
    void deleteRecordScreen() {
        cout << "------------" << endl;
        cout << "DELETE EMPLOYEE RECORDS" << endl;
        cout << left << setw(6) << "ID" << setw(15) << "NAME" << setw(10) << "JOB TITLE" << endl;
        for (const auto& employee : db.getAllEmployees()) {
            string formattedId = "(" + to_string(employee.get().userId) + ")";
            cout << left << setw(6) << formattedId;
            cout << setw(15) << employee.get().name << setw(10) << employee.get().jobTitle << endl;
        }
        cout << endl;
        cout << "------------" << endl;
        cout  << "Enter User ID to delete Employee Record. Press m to go back to Menu. Press q to quit to login screen." << endl;
        string employeeChoice;
        while(true) {
            cout  << "> ";
            cin >> employeeChoice;
            if (employeeChoice == "q") {
                this->quitToLoginScreen();
            }
            if (employeeChoice == "m") {
                this->displayMenu();
            }
            for (const auto& employee : db.getAllEmployees()) {
                if (to_string(employee.get().userId) == employeeChoice) {
                   db.removeEmployee(employee.get().userId);
                }
            }
          showSearchAndViewRecordScreen();
        }
    }
    void editRecordScreen(){
        cout << "------------" << endl;
        cout << "ALL EMPLOYEE RECORDS" << endl;
        cout << left << setw(6) << "ID" << setw(15) << "NAME" << setw(10) << "JOB TITLE" << endl;
        for (const auto& employee : db.getAllEmployees()) {
            string formattedId = "(" + to_string(employee.get().userId) + ")";
            cout << left << setw(6) << formattedId;
            cout << setw(15) << employee.get().name << setw(10) << employee.get().jobTitle << endl;
        }
        cout << endl;
        cout << "------------" << endl;
        cout  << "Enter User ID to update Employee Record. Press m to go back to Menu. Press q to quit to login screen." << endl;
        string employeeChoice;
        while(true) {
            cout  << "> ";
            cin >> employeeChoice;
            if (employeeChoice == "q") {
                this->quitToLoginScreen();
            }
            if (employeeChoice == "m") {
                this->displayMenu();
            }
            for (const auto& employee : db.getAllEmployees()) {
                if (to_string(employee.get().userId) == employeeChoice) {
                    string oldUserName = employee.get().userName;
                    string oldName = employee.get().name;
                    string oldPassword = employee.get().password;
                    string oldJobTitle = employee.get().jobTitle;
                    int userId = employee.get().userId;
                    string newName, newJobTitle, newUserName, newPassword;
                    cout << "UPDATE EMPLOYEE RECORD" << endl;
                    cout << "Enter new user's name: ";
                    cin.ignore();
                    getline(cin, newName);
                    cout << "Enter user's Job Title: ";
                    getline(cin, newJobTitle);
                    cout << "Enter user's username: ";
                    getline(cin, newUserName);
                    cout << "Enter user's password: ";
                    getline(cin, newPassword);
                    if (cin.fail()) {
                        cin.clear();
                        cin.ignore(1000, '\n');
                    } else {
                        if(newUserName.empty()) {
                            newUserName = oldUserName;
                        }
                        if(newName.empty()) {
                            newName = oldName;
                        }
                        if(newPassword.empty()) {
                            newPassword = oldPassword;
                        }
                        if(newJobTitle.empty()) {
                            newJobTitle = oldJobTitle;
                        }
                        // To simplify, remove the old employee object and add a new one with the same ID.
                        db.removeEmployee(userId);
                        Employee newEmployee(newUserName, newName, newPassword, newJobTitle, userId);
                        db.addEmployee(newEmployee);
                        cout << "Update Employee." << endl;
                        this->displayMenu();
                    }
                }
            }
          showSearchAndViewRecordScreen();
        }
    }
};


bool validateLogin(string userName, string password) {
    for (const auto& employee : db.getAllEmployees()) {
        if (employee.get().userName == userName && employee.get().password == password) {
            isLoggedIn = true;
            loggedInUser = employee.get();
            return true;
        }
     }
    return false;
}

void showEmployeeMenu() {
    loggedInUser.get().displayMenu();
 }

void showLoginScreen() {
    string userName;
    string password;
    cout << "Welcome to the Employee Management System. Please login to continue." << endl;
    cout << endl;
    cout << endl;
    while(true) {
        cout  << "Username: ";
        getline(cin, userName);
        if(!userName.empty()){
            break;
        } else {
            cout << "Invalid input. Please try again." << endl;
        }
    }
    while(true) {
        cout  << "Password: ";
        // Typically, we'd want to mask password input so as to not show on the screen.
        getline(cin, password);
        if(!password.empty()){
            break;
        } else {
            cout << "Invalid input. Please try again." << endl;
        }
    }
    // Authenticate the User by username and password and allow them to see their respective employee menu according to their permissions level.
    if (validateLogin(userName, password)){
        showEmployeeMenu();
    } else {
        cout << "%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%" << endl;
        cout << "% Invalid login credentials entered. Please try again. %" << endl;
        cout << "%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%" << endl;
        showLoginScreen();
    }
}

void showMainScreen() {
    if (!isLoggedIn) {
        showLoginScreen();
    } else {
        showEmployeeMenu();
    }
}

int main() {

    // Add example employees, these would typically be loaded from a database on program start.
    Employee employee1("bryan", "Bryan Paronto", "bryan", "Software Engineer");
    db.addEmployee(employee1);
    HumanResourcesEmployee hrPerson1("susan", "Susan Ross", "susan", "HR Personnel");
    db.addEmployee(hrPerson1);
    Manager manager1("manager", "Gob Bluth", "manager", "CEO of Banana Stand");
    db.addEmployee(manager1);

    // Start Program
    showMainScreen();

    return 0;
}