Updated March 17, 2023
Differences Between C# Abstract and Interface
Abstract class and Interface both are very much important methodologies to learn for understanding any object-oriented programming training. Normally both are very much confusing for the initial start of a learner on object-oriented programming. If we define one abstract class but do not implement anything, then it absolutely looks like Interface; no one will able to understand any difference between them rather than a declaration. However, there have a lot of differences and similarities available between the Interface and Abstract class.
An abstract class is a simple class which defines as abstract and could not be instantiated. An abstract class has to be extended by some subclasses for using all the features or utility of that specific superclass or abstract class. It actually helps to maintain the proper hierarchy of superclasses or subclasses. Multiple subclasses can use the same name of functionality with different definitions. It ensures the application should follow some specific hierarchy or standards that carry forward the application’s proper explainable functionality.
The interface is absolutely not a class; it just like an Entity which defined by one specific word Interface. Interface never defined any definition; it entirely depends on a specific declaration, which should inherit by multiple classes at the same time. Multiple classes can able to define multiple definitions of that individual declaration of one specific interface. It also holds the same kind of facility as the Abstract class; it mainly helps to maintain the same hierarchy of subclasses with a different definition. But the main difference between abstract class and Interface is extended of multiple abstract classes is not possible, whereas inherit of multiple interfaces is possible. As C# not supporting multiple inheritances, so the same kind of functionality provides by the interface.
Head To Head Comparison Between C# Abstract and Interface(Infographics)
Below is the Top Comparisons Between C# Abstract vs Interface
Key Differences Between C# Abstract and Interface
Some key differences are explained below between C# Abstract vs Interface
- Abstract class and Interface both are actually using by one or many subclasses. The main restriction is one subclass cannot able to extend multiple abstract classes means multiple inheritances cannot be possible, whereas the subclass can inherit multiple interfaces one time.
- The abstract can hold the body with a definition or only a definition of a method. Subclass, which extends that abstract class can use with body method and also can explain body details of any specific definition of the abstract method means overridden can be possible. The abstract class should have at least one abstract method (which means the only definition of the method without body). Interface only have the definition of the method; it should not contain any body details of the define method. One subclass inheritance that interface and utilises those does not define the method by giving proper body details dynamically for multiple subclasses.
- An abstract class can have different access modifiers like public, private or protected, so any method or properties inside the abstract class can define different access modifiers. Whereas for Interface can’t give any access modifier, all the properties or methods defined inside the interface should be public access modifier and don’t have the option to define another access modifier inside the interface.
- The superclass and subclass concept is exactly perfect for the abstract class. An abstract class can be given the core identity of a subclass; it normally holds a similar kind of object of that specific subclass. Whereas Interface normally defines one specific type of peripheral activity of a class. Suppose we have one interface name is Moveable, now this interface can be inherited by car and human both. Whereas cars and humans both are an entirely different class object and not holding any relationship between them.
- If the application has various implementation but the activity of that specific implementation almost the same, then better to use Abstract class, where you can define that specific logic, and all the subclass can easily access the same logic every time. For example, database connectivity, which is normally used by all the subclasses, so if this connectivity generation and closing code can hold in an abstract class, it will be very easy for any subclass to access the same. Whereas multiple implementations want to share only the signature of the method, then Interface is always better.
Comparison Table C# Abstract vs Interface
Following is the Comparison Table Between C# Abstract vs Interface
|Multiple inherit||One subclass can be only able to extend one abstract class, not multiple.||One subclass can able to implement multiple interfaces, which help to recover not supporting the multiple inheritance feature of C#.|
|Class definition||Interface never defines any specific body of a definition; it just holds the definition which implemented properly by the subclass later.||The abstract can hold the entire body with definition and also can hold the only definition like interface, which can be overridden by any subclasses. Any abstract class should have at least one abstract method which holding definition details only; the body will be described later in the subclass.|
|Access Modifier||Interface never has any access modifier in its definition. Interface normally consider all the properties as public.||An abstract class can have an access modifier for its definition. So all the properties can be public, private or protected.|
|Performance||Normally taken a little more time to find out the corresponding method of subclass.||It is a little faster than the interface.|
Interface and Abstract class are mainly used to manage multiple implementations in a smart way so that redundant code can easily be avoided and everything is in proper hierarchy and structure. The interface will always be better for sharing the same signature in multiple instances. Suppose Pantaloons have one main branch, and it also has multiple branches in a different location. One specific product can launch in a specific location with one approach, whereas in other locations, it launches in a different approach. In that case, logit ic, shobe uld different for the same product in multiple locations; this kind of logic be better handledndle by the interface. Now for the same product may have some common characteristics that need to be highlighted in every branch when launching that product. In that case, to avoid code redundancy, add that same logic in the abstract class and can use in multiple implementations in different branches.
This has been a useful guide to Differences Between C# Abstract vs Interface here; we have discussed head to head comparison, a key difference, and infographics. You may also look at the following article to learn more –