State

Each object has a state that may or may not differ from the state of other objects. We've already introduced the Product struct, which represents an abstraction of a physical (or digital) product. All the members of a product object collectively represent the state of the object. For example, the Product contains members such as available, which is a Boolean; it equals true if the product is in stock. The values of the member variables define the state of the object. If you assign new values to the object member, its state will change:

Product cpp_book; // declaring the object
...
// changing the state of the object cpp_book
cpp_book.available = true;
cpp_book.rating = 5;

The state of the object is the combination of all of its properties and values.