Difference Wiki

Constructor vs. Destructor: What's the Difference?

Edited by Huma Saeed || By Sumera Saeed || Updated on October 20, 2023
Constructor initializes an object; destructor cleans up resources.

Key Differences

A constructor is a special method in an object-oriented programming language that is automatically called when an object of a class is created. A destructor, on the other hand, is called when the object goes out of scope or is explicitly destroyed.
Sumera Saeed
Oct 20, 2023
The primary role of the constructor is to initialize the data members of the class and allocate memory if needed. The destructor, contrastingly, is responsible for deallocating the memory or cleaning up any resources that the object may have acquired during its lifetime.
Sumera Saeed
Oct 20, 2023
Both constructor and destructor have unique characteristics. For instance, a class can have multiple constructors with different parameters, but it can only have one destructor. This single destructor ensures that resources are released appropriately.
Sumera Saeed
Oct 20, 2023
The names of both constructor and destructor are defined by the programming language. In C++, the constructor has the same name as the class, while the destructor has the same name preceded by a tilde (~). Despite their differences, both constructor and destructor play pivotal roles in the lifecycle of an object.
Aimie Carlson
Oct 20, 2023
Even though both are essential, their timings differ. The constructor is invoked at the beginning of an object’s lifecycle, ensuring it's ready for use. The destructor, in contrast, marks the end of the object’s life, making sure no lingering resources remain.
Sumera Saeed
Oct 20, 2023
ADVERTISEMENT

Comparison Chart

Purpose

Initializes an object's state.
Cleans up resources and deallocates memory.
Sumera Saeed
Oct 20, 2023

Number in a class

Can have multiple with different parameters.
Only one per class.
Sumera Saeed
Oct 20, 2023

Naming in C++

Has the same name as the class.
Same name as the class but preceded by a tilde (~).
Sumera Saeed
Oct 20, 2023

Invocation

Automatically called when an object is created.
Called when an object is destroyed or goes out of scope.
Aimie Carlson
Oct 20, 2023

Resource management

Can allocate memory or resources.
Responsible for releasing memory or resources.
Aimie Carlson
Oct 20, 2023
ADVERTISEMENT

Constructor and Destructor Definitions

Constructor

A method that initializes an object.
The constructor set the initial value of the variable.
Huma Saeed
Oct 20, 2023

Destructor

A special routine in OOP invoked upon object destruction.
As the program ended, the object's destructor was called.
Aimie Carlson
Oct 20, 2023

Constructor

May be overloaded with different parameters.
The class had three constructors for varied data inputs.
Aimie Carlson
Oct 20, 2023

Destructor

A method that cleans up an object's resources.
The destructor ensured there were no memory leaks.
Huma Saeed
Oct 20, 2023

Constructor

A special routine of a class in OOP.
We defined a custom constructor for user inputs.
Sumera Saeed
Oct 20, 2023

Destructor

Helps in freeing the resources an object has consumed.
The file object's destructor closed the opened file.
Sumera Saeed
Oct 20, 2023

Constructor

Establishes default properties of an object.
The rectangle's constructor sets its default dimensions.
Sumera Saeed
Oct 20, 2023

Destructor

Marks the end of an object's lifecycle.
The vector's destructor released its dynamically allocated space.
Harlon Moss
Oct 20, 2023

Constructor

Initiates the instance variables of a class.
Without a proper constructor, the object might behave unpredictably.
Sumera Saeed
Oct 20, 2023

Destructor

Opposite of a constructor in terms of functionality.
While the constructor set up the environment, the destructor dismantled it.
Aimie Carlson
Oct 20, 2023

Constructor

To form by assembling or combining parts; build.
Sumera Saeed
Aug 23, 2017

Destructor

An incinerator for refuse.
Sumera Saeed
Aug 23, 2017

Destructor

An explosive, usually remote-controlled device for effecting a destruct.
Sumera Saeed
Aug 23, 2017

FAQs

What is a constructor?

A method that initializes an object when it's created.
Sumera Saeed
Oct 20, 2023

How does a destructor differ from a constructor?

A destructor cleans up resources when an object is destroyed, while a constructor initializes an object.
Huma Saeed
Oct 20, 2023

How many destructors can a class have?

Only one.
Janet White
Oct 20, 2023

Can constructors and destructors have return types?

No, they don't have return types.
Aimie Carlson
Oct 20, 2023

Is it mandatory to define a constructor or destructor for a class?

No, if not defined, the compiler provides default ones.
Janet White
Oct 20, 2023

Do all OOP languages support destructors?

Not all. Some languages rely on garbage collectors, reducing the need for explicit destructors.
Janet White
Oct 20, 2023

Do constructors and destructors perform the same tasks?

No, constructors initialize, while destructors clean up.
Harlon Moss
Oct 20, 2023

How are constructors and destructors named in C++?

Constructors have the same name as the class; destructors have the class name but preceded by a tilde (~).
Sumera Saeed
Oct 20, 2023

How do destructors aid in resource management?

They ensure that resources like memory, file handles, and network connections are released.
Aimie Carlson
Oct 20, 2023

Can a class have multiple constructors?

Yes, constructors can be overloaded with different parameters.
Sumera Saeed
Oct 20, 2023

When is a constructor called?

When an object of the class is instantiated.
Aimie Carlson
Oct 20, 2023

How do constructors and destructors work in inheritance?

Constructors are called top-down (base to derived), while destructors are called bottom-up (derived to base).
Sumera Saeed
Oct 20, 2023

Can we explicitly call constructors or destructors?

Constructors can be explicitly called, but it's not recommended. Destructors can be invoked using delete (in languages like C++), but not directly.
Harlon Moss
Oct 20, 2023

What's the significance of parameterized constructors?

They allow objects to be initialized with specific values.
Sumera Saeed
Oct 20, 2023

Can a destructor allocate resources?

Though technically possible, it's against its typical purpose.
Sumera Saeed
Oct 20, 2023

Why are destructors important?

They ensure resources like memory are properly released, preventing memory leaks.
Sumera Saeed
Oct 20, 2023

Why might a constructor fail?

Reasons include insufficient memory or invalid initial values.
Sara Rehman
Oct 20, 2023

What happens if an exception is thrown in a constructor or destructor?

If thrown in a constructor, the object creation fails. In a destructor, it might lead to a program termination or undefined behavior.
Aimie Carlson
Oct 20, 2023

What is the lifecycle of an object concerning constructors and destructors?

The constructor is called at the start, initializing the object, and the destructor at the end, cleaning up resources.
Sumera Saeed
Oct 20, 2023

When is a destructor invoked?

When an object is destroyed or goes out of scope.
Sumera Saeed
Oct 20, 2023
About Author
Written by
Sumera Saeed
Sumera is an experienced content writer and editor with a niche in comparative analysis. At Diffeence Wiki, she crafts clear and unbiased comparisons to guide readers in making informed decisions. With a dedication to thorough research and quality, Sumera's work stands out in the digital realm. Off the clock, she enjoys reading and exploring diverse cultures.
Edited by
Huma Saeed
Huma is a renowned researcher acclaimed for her innovative work in Difference Wiki. Her dedication has led to key breakthroughs, establishing her prominence in academia. Her contributions continually inspire and guide her field.

Trending Comparisons

Popular Comparisons

New Comparisons