# What Are the Common Examples of Variable Sized Data Structure Types?

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Angela Bailey

When it comes to data structures, there are various types that can be used to organize and manipulate data efficiently. One important aspect of data structures is their size, as it determines how much memory they occupy in the computer’s memory. In this article, we will explore some common examples of variable-sized data structure types.

## Arrays

An array is a fundamental data structure that can store a fixed-size sequence of elements of the same type. However, some programming languages allow for dynamic arrays, where the size can change during runtime. These arrays are known as variable-sized arrays.

Example:

int[] myArray = new int[10];

This creates an integer array with a fixed size of 10 elements. However, some programming languages provide features to resize the array dynamically as needed.

A linked list is another commonly used data structure that consists of nodes connected through pointers. Each node contains data and a reference to the next node in the list. The size of a linked list can vary dynamically as nodes are added or removed.

Example:

In C++:

``````struct Node {
int data;
Node* next;
};

// Creating a linked list with three nodes
Node* second = new Node();
Node* third = new Node();

second->data = 2;
second->next = third;

third->data = 3;
third->next = nullptr;``````

## Trees

Trees are hierarchical data structures that consist of nodes connected by edges. Each node can have any number of child nodes. The size of a tree can vary depending on the number of nodes it contains.

Example:

``````class Node {
int data;
Node left, right;
}

// Creating a binary tree with three nodes
Node root = new Node();
Node leftChild = new Node();
Node rightChild = new Node();

root.data = 1;
root.left = leftChild;
root.right = rightChild;``````

## Dynamic Arrays

A dynamic array is a resizable array that can grow or shrink in size as needed. It allocates memory dynamically to accommodate additional elements when the original capacity is reached. The size of a dynamic array can vary depending on the number of elements it holds.

Example:

In Python:

``````myList = [1, 2, 3]
myList.append(4) # Adding an element to the list dynamically``````

## Stacks and Queues

Stacks and queues are abstract data types that follow specific rules for adding and removing elements. Both can be implemented using arrays or linked lists. Their sizes can vary dynamically as elements are pushed or popped.

### Stacks

A stack is a Last-In-First-Out (LIFO) data structure, meaning that the last element added will be the first one to be removed.

### Queues

A queue is a First-In-First-Out (FIFO) data structure, where the first element added will be the first one to be removed.

## In Conclusion

Data structures come in various types and sizes, and it’s important to choose the right one based on the requirements of your program. Understanding variable-sized data structures like arrays, linked lists, trees, dynamic arrays, stacks, and queues can greatly enhance your ability to handle and manipulate data effectively.