Code Editor for app.py

import streamlit as st

st.title("Employee Salary Calculator Demo")

# Add explanation of the original issue
st.markdown("""
### Original Issue
The issue in the original code was that `Salary.pay` didn't update when `Employee.pay` changed because:
1. `Salary.pay` was just a copy of the value from `Employee.pay` at initialization
2. No reference was maintained between the two values after initialization

Below is the fixed code with proper value updating:
""")

# Fixed code implementation
class Employee:
    def __init__(self, pay, bonus):
        self.abc = 100
        self._pay = pay  # Using property to control access
        self.bonus = bonus
        self.obj_salary = Salary(self)
        self.annual_salary()
    
    # Property getter
    @property
    def pay(self):
        return self._pay
    
    # Property setter
    @pay.setter
    def pay(self, value):
        self._pay = value
 
    def annual_salary(self):
        total = self.obj_salary.get_total() + self.bonus
        st.write(f"Total Annual Salary: {total}")


class Salary:
    def __init__(self, parent):
        self.parent = parent
 
    # Instead of storing pay directly, we'll always get it from parent
    @property
    def pay(self):
        return self.parent.pay
 
    def get_total(self):
        st.write(f"ABC value: {self.parent.abc}")
        return (self.pay * 12)

# Demo the fixed code
obj_emp = Employee(600, 500)
st.write("Initial pay:", obj_emp.obj_salary.pay)

st.write("Changing pay to 700...")
obj_emp.pay = 700
st.write("Updated pay:", obj_emp.obj_salary.pay)

# Show annual salary calculation
obj_emp.annual_salary()

# Add explanation of the fix
st.markdown("""
### Explanation of the Fix

The code was fixed by:
1. Using the `@property` decorator to create proper getters and setters for the pay attribute
2. Having `Salary.pay` always reference the parent's pay value instead of storing a copy
3. This ensures that any updates to Employee's pay are reflected in Salary calculations

Now when you change `obj_emp.pay = 700`, the Salary object will use the updated value in its calculations.
""")