Question

with PHP Create a class called Invoice that a hardware store might use to represent an invoice for an item sold at the store. An Invoice should include four pieces of information as instance variables — a part number (type String), a part description (type String), a quantity of the item being purchased (type int) and a price per item (double). Your class should have a constructor that initializes the four instance variables. Provide a set and a get method for each instance variable. In addition, provide a method named getInvoiceAmount that calculates the invoice amount (i.e., multiplies the quantity by the price per item), then returns the amount as a double value. If the quantity is not positive, it should be set to 0. If the price per item is not positive, it should be set to 0.0. Write a test application named InvoiceTest that demonstrates class Invoice’s capabilities.

Answer 1

// file: invoice.php

<?php

// Invoice class
class Invoice
{
   public $part_number;
   public $part_description;
   public $quantity;
   public $price_per_item;
  
   // Constructor
   public function __construct($part_number, $part_description, $quantity, $price_per_item)
   {

       $this->part_number = $part_number;
       $this->part_description = $part_description;
       if($quantity < 0)
           $this->quantity = 0;
       else
           $this->quantity = quantity;
          
       if(price_per_item < 0)
           $this->price_per_item = 0;
       else
           $this->price_per_item = price_per_item;
   }
  
   // getters
   public function get_partnumber()
   {
       return $this->part_number;
   }
  
   public function get_partdescription()
   {
       return $this->part_description;
   }
  
   public function get_quantity()
   {
       return $this->quantity;
   }
  
   public function get_priceperitem()
   {
       return $this->price_per_item;
   }
  
   // setters
   public function set_partnumber($part_number)
   {
       $this->part_number = $part_number;
   }
  
   public function set_partdescription($part_description)
   {
       $this->part_description = $part_description;
   }
  
   public function set_quantity($quantity)
   {
       if($quantity > 0)
           $this->quantity = $quantity;
       else
           $this->quantity = 0;
   }
  
   public function set_priceperitem($price_per_item)
   {
       if($price_per_item > 0)
           $this->price_per_item = price_per_item;
       else
           $this->price_per_item = 0;
   }
  
   // method to calculate the total invoice amount
   public function getInvoiceAmount ()
   {
       return($this->quantity*$this->price_per_item);
   }

}//end class Invoice
?>

//end of invoice.php

//file : invoiceTest.php

<?php

include("invoice.php");
  
$invoice1 = new Invoice('P001','Nut',10,2.5);

print('Part Number : '.$invoice1->get_partnumber().', Part Description : '.$invoice1->get_partdescription().' Quantity : '.$invoice1->get_quantity().' Price per item : $'.$invoice1->get_priceperitem().' Invoice Amount : $'.$invoice1->getInvoiceAmount());
?>

//end of invoiceTest.php