PersonnelManagementSystem.java

import java.util.Scanner;

// Base Class
class Employee {
    private String name;
    private int employeeId;

    // Parameterized constructor
    public Employee(String name, int employeeId) {
        this.name = name;
        this.employeeId = employeeId;
    }

    public String getName() { return name; }
    public int getEmployeeId() { return employeeId; }

    // Base method to calculate salary (designed to be overridden)
    public double calculateSalary() {
        return 0.0;
    }

    // Overloaded method to calculate salary with a bonus
    public double calculateSalary(double bonus) {
        return calculateSalary() + bonus;
    }

    // Display employee details
    public void display() {
        System.out.println("Employee ID: " + employeeId + " | Name: " + name);
    }
}

// Subclass for Full-Time Employee
class FullTimeEmployee extends Employee {
    private double monthlySalary;

    // Constructor to initialize full-time employee details
    public FullTimeEmployee(String name, int employeeId, double monthlySalary) {
        super(name, employeeId);
        this.monthlySalary = monthlySalary;
    }

    // Overriding the base method
    @Override
    public double calculateSalary() {
        return monthlySalary;
    }
}

// Subclass for Part-Time Employee
class PartTimeEmployee extends Employee {
    private double hourlyRate;
    private int hoursWorked;

    // Constructor to initialize part-time employee details
    public PartTimeEmployee(String name, int employeeId, double hourlyRate, int hoursWorked) {
        super(name, employeeId);
        this.hourlyRate = hourlyRate;
        this.hoursWorked = hoursWorked;
    }

    // Overriding the base method
    @Override
    public double calculateSalary() {
        return hourlyRate * hoursWorked;
    }
}

// Main Driver Class
public class PersonnelManagementSystem {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        // --- 1. Full-Time Employee Input ---
        System.out.println("--- Full-Time Employee Data Entry ---");
        System.out.print("Enter Name: ");
        String ftName = scanner.nextLine();
        
        System.out.print("Enter ID: ");
        int ftId = getValidInt(scanner);
        
        System.out.print("Enter Base Monthly Salary: ");
        double ftSalary = getValidDouble(scanner);
        
        System.out.print("Enter Bonus Amount: ");
        double ftBonus = getValidDouble(scanner);

        FullTimeEmployee fullTime = new FullTimeEmployee(ftName, ftId, ftSalary);

        // --- 2. Part-Time Employee Input ---
        System.out.println("\n--- Part-Time Employee Data Entry ---");
        scanner.nextLine(); // Consume the leftover newline from previous numeric inputs
        
        System.out.print("Enter Name: ");
        String ptName = scanner.nextLine();
        
        System.out.print("Enter ID: ");
        int ptId = getValidInt(scanner);
        
        System.out.print("Enter Hourly Rate: ");
        double ptRate = getValidDouble(scanner);
        
        System.out.print("Enter Hours Worked: ");
        int ptHours = getValidInt(scanner);
        
        System.out.print("Enter Bonus Amount: ");
        double ptBonus = getValidDouble(scanner);

        PartTimeEmployee partTime = new PartTimeEmployee(ptName, ptId, ptRate, ptHours);

        // --- 3. Display Results ---
        System.out.println("\n========================================");
        System.out.println("          EMPLOYEE DETAILS");
        System.out.println("========================================");

        // Demonstrate Overriding & Overloading for Full-Time
        System.out.println("[Full-Time Employee]");
        fullTime.display();
        System.out.println("Base Salary: " + fullTime.calculateSalary());
        System.out.println("Salary with Bonus: " + fullTime.calculateSalary(ftBonus));
        System.out.println("----------------------------------------");

        // Demonstrate Overriding & Overloading for Part-Time
        System.out.println("[Part-Time Employee]");
        partTime.display();
        System.out.println("Base Salary (Rate x Hours): " + partTime.calculateSalary());
        System.out.println("Salary with Bonus: " + partTime.calculateSalary(ptBonus));
        System.out.println("========================================");

        scanner.close();
    }

    // --- Helper Methods to Prevent Scanner Crashes ---
    
    private static int getValidInt(Scanner scanner) {
        while (!scanner.hasNextInt()) {
            System.out.print("Invalid input. Please enter a valid whole number: ");
            scanner.next(); // Consume invalid input
        }
        return scanner.nextInt();
    }

    private static double getValidDouble(Scanner scanner) {
        while (!scanner.hasNextDouble()) {
            System.out.print("Invalid input. Please enter a valid number: ");
            scanner.next(); // Consume invalid input
        }
        return scanner.nextDouble();
    }
}