Project Question: Electricity Bill Calculator

Objective:

Develop a Java application that calculates and displays the electricity bill for a customer based on their meter readings. The application should validate input data, perform necessary calculations, and display the bill details in a formatted manner.

Requirements:

1. Input Data:

   • Customer Number (String)
   • Customer Name (String)
   • Old Meter Reading (Integer)
   • Current Meter Reading (Integer)
   • Fixed Rental and Line Maintenance Charges (Constant: Rs. 250)

2. Validation:

   • Ensure the old meter reading is not greater than the current meter reading.
   • If invalid data is detected, display an error message and terminate the program.

3. Calculations:

   • Calculate the total units consumed: unitsUsed = currentReading - oldReading.
   • Calculate the usage amount based on the units consumed:
     • If unitsUsed is less than or equal to 100 units, userAmount = unitsUsed * 3.25.
     • If unitsUsed is greater than 100 units, userAmount = 325 + ((unitsUsed - 100) * 4.75).
   • Calculate the tax (11.5% of the usage amount): tax = userAmount * 11.5 / 100.
   • Calculate the total bill: bill = RENTAL_AMOUNT + userAmount + tax.

4. Output:

   • Display the bill details including:
     • Customer Number
     • Customer Name
     • Old Meter Reading
     • Current Meter Reading
     • Total Units Consumed
     • Fixed Rental and Line Maintenance Charges
     • Total Usage Amount
     • Tax
     • Total Bill Amount Payable

Sample Output:

        WEST BENGAL BIJLI VITRAN LIMITED 
        A GOVT. OF HARYANA UNDERTAKING
Customer Number: hg654
Customer Name: Rumman Ansari
Old Meter Reading: 2562
Current Meter Reading: 2892
Total Units Consumed: 330
Fixed Rental & Line Maintenance Charges: Rs.250
Total usage: Rs.1067
Tax (11.5%): Rs.123
-------------------------------------
Total Bill Amount Payable: Rs.1440

Implementation Steps:

1. Setup the Development Environment:

   • Install a Java Development Kit (JDK) if not already installed.
   • Use an Integrated Development Environment (IDE) like Eclipse or IntelliJ IDEA.

2. Define the Class:

   • Create a class ElectricityBill with the main method.

3. Implement Input Handling:

   • Declare variables for customer details and meter readings.
   • Initialize sample data for the purpose of this project.

4. Add Validation Logic:

   • Check if the old meter reading is greater than the current meter reading.

5. Implement Calculation Logic:

   • Calculate unitsUsed, userAmount, tax, and bill as per the given logic.

6. Display the Bill:

   • Use System.out.println to print the bill details in a formatted manner.

7. Test the Application:

   • Run the program with different inputs to ensure it works correctly and handles errors as expected.

Extension Ideas:

• Allow user input via the console instead of using hardcoded sample data.
• Add functionality to read input from a file and write the output to a file.
• Implement a graphical user interface (GUI) for a better user experience.

This project will help you understand basic Java programming concepts, including input validation, arithmetic operations, conditional statements, and formatted output.