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Table of contents
Understanding Dynamic Constructors
Why Use Dynamic Constructors?
Dynamic Constructors in Action
Key Things to Remember
Frequently Asked Questions
What is a dynamic constructor in C++?
Why use dynamic constructors?
How can memory leaks be avoided with dynamic constructors?
Last Updated: Mar 27, 2024

Dynamic constructor in C++

Author Ravi Khorwal
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C++ is a versatile language known for its ability to deal with complex object-oriented programming concepts. Among these, constructors play a vital role, especially when it comes to dynamic memory allocation. Dynamic constructors in C++ are a fascinating feature that broadens the scope of object creation and memory utilization. 

Dynamic Constructors in C++

In this article, we'll delve into the intricacies of dynamic constructors in C++, exploring their definition, how they work, and providing practical examples for clearer understanding.

Understanding Dynamic Constructors

In C++, a dynamic constructor is a special type of constructor used for objects that require memory allocation at runtime. It's called "dynamic" because it doesn't reserve memory when the object is declared but instead allocates it when the object is instantiated, i.e., during runtime.

Why Use Dynamic Constructors?

Dynamic constructors can optimize memory usage, particularly when you need to declare objects with variable sizes. With dynamic constructors, memory allocation for an object occurs only if it is required, preventing unnecessary memory wastage.

Dynamic Constructors in Action

Here's a simple example of a dynamic constructor.

class DynamicArray {
    int* arr;
    // Dynamic Constructor
    DynamicArray(int size) {
        arr = new int[size];  // Dynamic memory allocation

    // Destructor
    ~DynamicArray() {
        delete[] arr;

In this example, the DynamicArray class has a dynamic constructor that allocates memory for an integer array of variable size. When an object of the DynamicArray class is created with a specific size, the dynamic constructor allocates the necessary memory. The destructor then frees up the dynamically allocated memory when the object goes out of scope, avoiding memory leaks.

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Key Things to Remember

While dynamic constructors can be a powerful tool, they also need to be used responsibly. You must ensure that any dynamically allocated memory is released using a destructor to avoid memory leaks. Failing to do so could result in issues that are often difficult to diagnose and fix.

Also read -  File Handling in CPP

Frequently Asked Questions

What is a dynamic constructor in C++?

A dynamic constructor in C++ is a constructor that performs dynamic memory allocation during object instantiation.

Why use dynamic constructors?

Dynamic constructors are used to optimize memory usage by allocating memory for objects at runtime, preventing unnecessary memory wastage.

How can memory leaks be avoided with dynamic constructors?

Memory leaks can be avoided by releasing the dynamically allocated memory using a destructor when the object goes out of scope.


Dynamic constructors in C++ offer a flexible and efficient way to handle memory allocation for objects. However, they should be used judiciously and always paired with an appropriate destructor to manage the dynamically allocated memory effectively. The more you understand about these dynamic constructors, the more you can harness the full power of C++ to create efficient and effective programs.

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