My project is an Employee Management System built in Python.

Quick Bulleted Summary **
**Project Name: Employee Management System

1. Language: Python

2. Core Concepts: OOP (Inheritance, Polymorphism, Encapsulation, Abstraction)

3. Architecture:

4. Base Class: Employee (holds common private data: ID, Name, Age)

5. Child Classes: FullTimeEmployee, PartTimeEmployee (inherit from Employee, override calculate_salary())

6. Manager Class: EmployeeManager (handles CRUD operations: Create, Read, Update, Delete using a list)

7. Features: Add Employee, Remove Employee, Search by ID, Display All Employees.

8. User Interface: Command-line interactive menu using a while loop and if/elif conditions.
   

# ============================================
# EMPLOYEE MANAGEMENT SYSTEM
# OOP Concepts: Class, Object, Encapsulation,
# Inheritance, Polymorphism, Abstraction
# ============================================

# ---------- BASE CLASS (Abstraction + Encapsulation) ----------
class Employee:
    def __init__(self, emp_id, name, age):
        self.__emp_id = emp_id     # private
        self.__name = name         # private
        self.__age = age           # private

    # Getter methods
    def get_id(self):
        return self.__emp_id

    def get_name(self):
        return self.__name

    def get_age(self):
        return self.__age

    # Setter methods
    def set_name(self, name):
        self.__name = name

    def set_age(self, age):
        if age > 0:
            self.__age = age

    # Method to be overridden (Polymorphism)
    def calculate_salary(self):
        return 0

    def display(self):
        print("ID    :", self.__emp_id)
        print("Name  :", self.__name)
        print("Age   :", self.__age)


# ---------- DERIVED CLASS 1 (Inheritance) ----------
class FullTimeEmployee(Employee):
    def __init__(self, emp_id, name, age, monthly_salary):
        super().__init__(emp_id, name, age)
        self.monthly_salary = monthly_salary

    # Method Overriding (Polymorphism)
    def calculate_salary(self):
        return self.monthly_salary

    def display(self):
        super().display()
        print("Type  : Full-Time")
        print("Salary:", self.calculate_salary())


# ---------- DERIVED CLASS 2 (Inheritance) ----------
class PartTimeEmployee(Employee):
    def __init__(self, emp_id, name, age, hours_worked, rate_per_hour):
        super().__init__(emp_id, name, age)
        self.hours_worked = hours_worked
        self.rate_per_hour = rate_per_hour

    # Method Overriding (Polymorphism)
    def calculate_salary(self):
        return self.hours_worked * self.rate_per_hour

    def display(self):
        super().display()
        print("Type  : Part-Time")
        print("Salary:", self.calculate_salary())


# ---------- MANAGER CLASS ----------
class EmployeeManager:
    def __init__(self):
        self.employees = []   # list of objects

    def add_employee(self, emp):
        self.employees.append(emp)
        print("Employee added successfully!")

    def remove_employee(self, emp_id):
        for emp in self.employees:
            if emp.get_id() == emp_id:
                self.employees.remove(emp)
                print("Employee removed!")
                return
        print("Employee not found.")

    def search_employee(self, emp_id):
        for emp in self.employees:
            if emp.get_id() == emp_id:
                print("Employee Found:")
                emp.display()
                return
        print("Employee not found.")

    def display_all(self):
        if len(self.employees) == 0:
            print("No employees to display.")
            return
        print("----- All Employees -----")
        for emp in self.employees:
            emp.display()
            print("-------------------------")


# ---------- MAIN MENU ----------
def main():
    manager = EmployeeManager()

    while True:
        print("\n===== EMPLOYEE MANAGEMENT SYSTEM =====")
        print("1. Add Full-Time Employee")
        print("2. Add Part-Time Employee")
        print("3. Remove Employee")
        print("4. Search Employee")
        print("5. Display All Employees")
        print("6. Exit")
        choice = int(input("Enter your choice: "))

        if choice == 1:
            eid  = int(input("Enter ID: "))
            name = input("Enter Name: ")
            age  = int(input("Enter Age: "))
            sal  = float(input("Enter Monthly Salary: "))
            e = FullTimeEmployee(eid, name, age, sal)
            manager.add_employee(e)

        elif choice == 2:
            eid   = int(input("Enter ID: "))
            name  = input("Enter Name: ")
            age   = int(input("Enter Age: "))
            hours = float(input("Enter Hours Worked: "))
            rate  = float(input("Enter Rate per Hour: "))
            e = PartTimeEmployee(eid, name, age, hours, rate)
            manager.add_employee(e)

        elif choice == 3:
            eid = int(input("Enter Employee ID to remove: "))
            manager.remove_employee(eid)

        elif choice == 4: 
            eid = int(input("Enter Employee ID to search: "))
            manager.search_employee(eid)

        elif choice == 5:
            manager.display_all()

        elif choice == 6:
            print("Thank you! Exiting...")
            break

        else:
            print("Invalid choice. Try again.")

# ---------- PROGRAM ENTRY POINT ----------
if __name__ == "__main__":
    main()