What is the Difference Between Abstract Class and Interface in PHP

Abstract class contains both incomplete(i.e. abstract) and complete members. Since everything is assumed to be public, an interface class does not have access modifiers by default. An abstract class can contain access modifiers within subs, functions, and properties. Any member of an interface cannot be static.

1. What is difference between abstract class and interface?
2. Why do we use abstract class and interface in PHP?
3. What is the difference between an abstract class and an interface and when would you use one over the other?
4. What is abstract class in PHP?
5. How do you implement an abstract class?
6. Can we inherit abstract class?
7. What is the use of interface?
8. When should we use interface?
9. Can we replace abstract class with interface?
10. Can abstract class have constructor?
11. Can you instantiate an abstract class?
12. What is difference between class and interface?

What is difference between abstract class and interface?

Abstract class can inherit another class using extends keyword and implement an interface. Interface can inherit only an inteface. Abstract class can be inherited using extends keyword. Interface can only be implemented using implements keyword.

Why do we use abstract class and interface in PHP?

In PHP you can use interfaces define common functionality that is provided my similar classes. Abstract classes are used to define base classes that provide common functionality. Despite interfaces and abstract classes are somewhat related, they are not the same.

What is the difference between an abstract class and an interface and when would you use one over the other?

The short answer: An abstract class allows you to create functionality that subclasses can implement or override. An interface only allows you to define functionality, not implement it. And whereas a class can extend only one abstract class, it can take advantage of multiple interfaces.

What is abstract class in PHP?

Abstract classes and methods are when the parent class has a named method, but need its child class(es) to fill out the tasks. An abstract class is a class that contains at least one abstract method. An abstract method is a method that is declared, but not implemented in the code.

How do you implement an abstract class?

Abstract class in Java

1. An abstract class must be declared with an abstract keyword.
2. It can have abstract and non-abstract methods.
3. It cannot be instantiated.
4. It can have constructors and static methods also.
5. It can have final methods which will force the subclass not to change the body of the method.

Can we inherit abstract class?

An abstract class defines the identity of a class. An interface can inherit multiple interfaces but cannot inherit a class. An abstract class can inherit a class and multiple interfaces. ... An abstract class can declare constructors and destructors.

What is the use of interface?

You use an interface to define a protocol of behavior that can be implemented by any class anywhere in the class hierarchy. Interfaces are useful for the following: Capturing similarities among unrelated classes without artificially forcing a class relationship.

When should we use interface?

One reason to use interfaces is when a class will implement a number of interfaces. An abstract class cannot do that. One example is a class which handles mouse movement and key presses will implement both the (ficticious) IMouseMove and IKeyPress interfaces. Also, using interfaces eases unit testing.

Can we replace abstract class with interface?

To answer your question, yes you could use an abstract class (providing no implementation) instead of an interface but I'd consider this bad practice: You've used up your "one-shot" at inheritance (without gaining any benefit). You cannot inherit from multiple abstract classes but you can implement multiple interfaces.

Can abstract class have constructor?

The constructor inside the abstract class can only be called during constructor chaining i.e. when we create an instance of sub-classes. This is also one of the reasons abstract class can have a constructor.

Can you instantiate an abstract class?

Abstract classes cannot be instantiated, but they can be subclassed. When an abstract class is subclassed, the subclass usually provides implementations for all of the abstract methods in its parent class. However, if it does not, then the subclass must also be declared abstract .

What is difference between class and interface?

A class describes the attributes and behaviors of an object. An interface contains behaviors that a class implements. A class may contain abstract methods, concrete methods. An interface contains only abstract methods.