Chapter 12, Problem 2PE

Program Plan Intro

Invoice

Program plan:

Filename: “Address.java”

This program file is used to define a class “Address”. In the code,

• Define a class “Address”.
  • Define the class members.
  • Define a constructor “Address()”.
    • Set the values for class members.
  • Define a method “format()”.
    • Return the address.

Filename: “Invoice.java”

This program file is used to define a class “Invoice”. In the code,

• Import the required packages.
• Define a class “Invoice”.
  • Define the class members.
  • Define a constructor “Invoice()”.
    • Set the class elements.
  • Define the method “add()”.
    • Create an object “anItem” of class “LineItem”.
    • Call the method “add()” recursively.
  • Define a class “format()”.
    • Define the constants “DESCRIPTION_WIDTH”, “PRICE_WIDTH”, “QTY_WIDTH”, “TOTAL_WIDTH”.
    • Define a string variable “r”.
    • Define an array “widths[]”.
    • Assign the constants of width to the array “widths[]”.
    • Iterate a “for” loop,
      • Call the method “format(widths)” and add the result to “r”.
        • Call the method “format” and add the result to “r”.
        • Return “r”.
  • Define a method “getAmountDue()”.
    • Define the variable “amountDue”.
    • Iterate a “for” loop,
      • Calculate the value of “amountDue”.
        • Return the value of “amountDue”.

Filename: “LineItem.java”

This program file is used to define a class “LineItem”. In the code,

• Import the required packages.
• Define a class “LineItem”.
  • Define the class members.
  • Define a constructor “LineItem()”.
    • Set the class elements.
  • Define a method “getTotalPrice()”.
    • Multiply the price and quantity and return the result.
  • Define the method “format”.
    • Define the variables.
    • Call the method “getDescription()” and assign the value to “description”.
    • Call the method “getCurrencyInstance()”.
    • Define a string “r” to hold the formatted details of a product.
    • Return the value of “r”.

Filename: “Product.java”

This program file is used to define a class “Product”. In the code,

• Import the required packages.
• Define a class “Product”.
  • Define the class members.
  • Define a constructor “Product()”.
    • Set the class elements.
  • Define a method “getDescription()”.
    • Return the “description”.
  • Define a method “getPrice()”.
    • Return the “price”.

Filename: “InvoicePrinter.java”

This program file is used to define a class “InvoicePrinter”. In the code,

• Define a class “InvoicePrinter”.
  • Define a method “main()”.
    • Define the object “samsAddress” of class “Address”.
    • Define the object “samsInvoice” of class “Invoice”.
    • Call the method “add()” using “samsInvoice” to add the products.
    • Print the invoice using “samsInvoice”.