The Real Reason We Call Them 'Constructors' : Real life vs OOP

Hi, before we dive in, just wanted to mention that I originally published this post as a blog on Hashnode with the same title- The Real Reason We Call Them 'Constructors' : Real life vs OOP

Reposting it here in case it offers a fun read or helps someone out!

A quick heads-up before we start — there’s a short recap section at the end. Feel free to skip ahead if you're short on time. I won’t mind!

Have you ever wondered what’s the connection between constructors in real life and constructors in OOP ? I mean, why do we call them “constructors” in OOP?

The screen shot above is the definition of the word “Constructors” we know in real life. In the world of computer science, constructors play a surprisingly similar role. (Even if it might not feel that way when you first hear the technical definition.)

Why? Let’s find out.

But first, let’s take a moment, and talk about the car company you have in real life.

Constructors in Real life:

Remember, you have an automobile company since my post about classes and objects?

Yes, you still have that.

Your company definitely has a team of engineers who conduct R&D about different aspects of vehicles like body, chassis, noise, vibration, design, aerodynamics etc. From this, they develop a new model or blueprint of your vehicles. At this moment, this model is just some words, metrics, tables and diagrams in papers.

Now you have your manufacturing team. This team assembles all the tools and gadgets needed, and builds the vehicle in accordance with the model or blueprint provided by your engineering team. In one word, they “construct” your vehicle according to the blueprint.

You probably have a sense of what constructors do in OOP by now. Still, let’s break down the technical side too. We’re done with the real-world part — now, on to the virtual-world.

Constructors in OOP:

I am sure you have heard how a “constructor” is a special type of function or method which_ “initializes the object's attributes or performs any setup required”_.

Sounds familiar ? We have just talked about how your engineering team provides the blueprint, and your manufacturing team “constructs” the vehicle.

In OOP, we know classes are the blueprint/model/design plan to create objects (a real-life thing).

You have designed your blueprint aka class CAR to store data during my blog about “classes and objects”. After defining your CAR class, when you try to create the object –a virtual car, you just give the instruction. The constructor does the rest for you.

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  It allocates the space in the memory. Think of it like allocating a space in the garage to keep the car.


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  Then it creates or constructs the object –a virtual car according to the attributes you have set in your class. Maybe you set the “color” of your CAR object to “red”, so it sets the color of the virtual car to red, maybe engine_type to “electric” and so on.

This whole "endeavor" is summed up in technical terms by a single line - “initializes the object's attributes or performs any setup required”. I think it’s fair to say we now understand why they’re called “constructors” in OOP.

With that being said, our conversation should end here.

But before we wrap up, here are some basic facts about constructors I think you should know.

Some Facts About Constructors in OOP:

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  Memory Allocation -The memory allocation depends on different types of** Data Structure**, another important and big topic in computer science. (Briefly saying, Data structure = Data + structure; the structure to store data efficiently).


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  Definition in Code - You can define your constructor explicitly with the attributes you want your object to have by default. But even if you don’t define the constructor, a default constructor is provided by the compiler. Though this constructor does not have any default values for the objects.


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  Calling - Another important fact about constructors is – it is automatically called, you don’t have to call it like you do in case of other methods or functions. This is why constructors are special type functions or methods.
  Now, I am ending my explanation here. Because the further explanation and coding syntax depends on different languages. For that, we’ve got plenty of amazing resources and articles available. Moreover, we have google and chatgpt.

Before ending, I’d like to briefly mention destructors.

Like the name suggests, it destroys the object after it fulfills its use. Think of it like creating a car “for a test”, then destroying it. (no sane and sober person destroys his/her car otherwise. So think of it as a test🙂).

Why do we need destructors? – to make space in the memory by deleting unnecessary objects. To put it technically, it’s for better memory management. You know, our memory size is limited.

Different programming languages have different ways to manage this “destroying” task.

So this is it. I’ve always been curious about what real-life constructors have in common with those in Computer Science, so I tried to explain it from that angle. I hope you found it helpful.

Finally, a quick recap:

• Constructors are used to construct or build objects for us when we try to create an object of a class. Just like we know in real life.
  


• Constructors allocate memory (allocates a space to keep the virtual car in the virtual garage.)


• Constructors set the default values of the attributes. (set the engine, color etc. of the car with the value we specified)
  


• We can explicitly define the constructor. If we don’t, a default constructor **is provided by the **compiler.


• We don’t have to call the “constructor” method like other methods or functions. It is called automatically when we give commands to create an object of a class.

Briefly mentioned:

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  Data Structure – the structure to store data efficiently


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  Destructor - destroys the unnecessary objects for better memory management.

Still thinking about what to write next. Let’s see where it goes.

But for now, Adios!