PROGRAMMING IN PHP - UNIT III

What is the purpose of the `final` keyword in PHP classes?

• The `final` keyword allows multiple inheritance in PHP.

• The `final` keyword enables method overloading in PHP.

• The `final` keyword prevents class inheritance and method overriding in PHP.

• The `final` keyword is used to define abstract classes in PHP.

Explain the concept of interfaces in PHP and how they differ from abstract classes.

• Interfaces in PHP define a contract for classes to implement, allowing multiple inheritance, while abstract classes can provide method implementations and properties, allowing only single inheritance.

• Interfaces can contain properties and method implementations.

• Abstract classes cannot have any method implementations.

• Interfaces can only be used in single inheritance scenarios.

What are traits in PHP and how do they help in code reuse?

• Traits in PHP are reusable sets of methods that allow multiple classes to share functionality without traditional inheritance, promoting code reuse.

• Traits are a form of database connection in PHP.

• Traits can only be used in a single class.

• Traits are a type of variable in PHP.

Describe the visibility keywords in PHP and their significance.

• The visibility keywords in PHP are 'static', 'final', and 'abstract'.

• Visibility keywords in PHP are used to define the data types of variables.

• The visibility keywords in PHP are 'global', 'local', and 'internal'.

• The visibility keywords in PHP are 'public', 'protected', and 'private', which control access to class properties and methods.

How does PHP handle method overloading and overriding?

• PHP supports both method overloading and overriding.

• PHP does not support method overriding but allows method overloading.

• PHP allows method overloading with default parameters.

• PHP handles method overriding but does not support method overloading.

What is the difference between static and instance methods in PHP?

• Static methods can access instance properties directly.

• Instance methods can be called without creating an object.

• Static methods require an object to be called.

• Static methods are called on the class itself and do not require an instance, while instance methods require an object of the class and can access instance properties.

Explain the concept of namespaces in PHP and their benefits.

• Namespaces are a type of variable in PHP.

• Namespaces are a way to define constants in PHP.

• Namespaces help organize code, prevent name conflicts, and improve code readability and maintainability.

• Namespaces are only used for database connections.

What is the purpose of the `__construct` and `__destruct` methods in PHP?

• The `__construct` method is used to create static methods, while the `__destruct` method is for managing session data.

• The `__construct` method is used for error handling, while the `__destruct` method is for logging.

• The `__construct` method is for defining constants, and the `__destruct` method is for setting up database connections.

• The `__construct` method initializes an object, while the `__destruct` method cleans up before the object is destroyed.

How can you implement polymorphism in PHP?

• Use interfaces or abstract classes to define common methods, allowing different classes to implement or override them.

• Implement polymorphism by using only public properties in classes.

• Use only static methods in classes to achieve polymorphism.

• Create multiple classes with identical method names but no common interface.

What are the advantages of using object-oriented programming in PHP?

• Advantages of using object-oriented programming in PHP include code reusability, improved maintainability, better organization, encapsulation, inheritance, and polymorphism.

• Simplified syntax for all programming tasks

• Increased execution speed

• Direct access to hardware resources