Create an XML file products.xml and store information including

the product id,

product name,

product quantity,

and

price

of the product.

Product id is an attribute while the other fields are represented as entities in the XML file.

The XML file should contain at least two product elements.

Check if the XML file is well-formed or not.

Create an internal DTD to validate the XML file. Check if the XML file is valid or not.