In PHP object oriented programming, what is the difference between the __construct() and __destruct() magic methods and when is each of them called?

Introduction / Context:
PHP supports object oriented programming with special magic methods that the engine calls at specific moments. Two of the most important magic methods are __construct() and __destruct(), which mark the lifecycle of an object. This question asks you to identify the role of each method and when it is invoked by the PHP runtime.

Given Data / Assumptions:

• We are working in PHP with classes and objects.
• __construct() and __destruct() are method names that follow a double underscore pattern.
• We are interested in when these methods run in relation to object creation and destruction.
• We assume standard PHP memory management and garbage collection rules.

Concept / Approach:
The constructor method, named __construct(), is called automatically when you create a new instance of a class with the new keyword. It is typically used to initialize properties, open resources, or perform any setup code required by the object. The destructor method, named __destruct(), is called automatically when the object is about to be destroyed, such as when it goes out of scope or when script execution ends. Destructors are often used to release resources like file handles or database connections.

Step-by-Step Solution:
1. Recall that constructors are special methods that prepare an object immediately after it is instantiated. 2. In PHP, the constructor magic method is named __construct() and does not need to be called manually in normal usage. 3. Remember that destructors are special methods that clean up resources when an object is no longer needed. 4. In PHP, the destructor magic method is named __destruct(), and the engine calls it when the object is about to be garbage collected or when the script ends. 5. Choose the option that correctly associates __construct() with object creation and __destruct() with object destruction.

Verification / Alternative check:
You can verify this behaviour by writing a simple class that echoes messages from its constructor and destructor. When you instantiate the class, you will see the constructor message immediately. When the script finishes or when you unset the object, you will see the destructor message. This direct experiment demonstrates that __construct() is tied to creation and __destruct() is tied to destruction, without needing manual calls in normal patterns.

Why Other Options Are Wrong:

• Option B is wrong because it reverses the roles of the two methods; constructors are not used for deletion.
• Option C is wrong because these are magic methods that the runtime calls automatically; manual calls are possible but not the typical use case.
• Option D is wrong because constructors and destructors do not define constants or properties; they are lifecycle hooks, not declarations.

Common Pitfalls:
One common pitfall is assuming that destructors always run at a precise time, which may not be true when circular references or complex garbage collection scenarios exist. Another mistake is performing heavy logic in destructors, which can complicate error handling. Developers should also avoid relying on destructors for critical tasks such as final database commits, and instead manage such tasks explicitly. Constructors, on the other hand, should be used carefully to avoid side effects that make objects difficult to test.

Final Answer:
The correct explanation is __construct() is automatically called when a new object instance is created, while __destruct() is automatically called when the object is about to be destroyed or script execution ends, because this describes the intended lifecycle roles of these two PHP magic methods.