Skip to content

Courses
Tutorials
Practice
Contests

C++ Data Types
C++ Input/Output
C++ Arrays
C++ Pointers
C++ OOPs
C++ STL
C++ Interview Questions
C++ Programs
C++ Cheatsheet
C++ MCQ
C++ Projects
C++ Exception Handling
C++ Memory Management

What are the data types for which it is not possible to create an array?

Variable Length Arrays (VLAs) in C

Last Updated : 10 Jan, 2025

Comments

Improve

Suggest changes

Like Article

Like

Report

In C, variable length arrays (VLAs) are also known as runtime-sized or variable-sized arrays. The size of such arrays is defined at run-time.

Variably modified types include variable-length arrays and pointers to variable-length arrays. Variably changed types must be declared at either block scope or function prototype scope.

Variable length arrays are a feature where we can allocate an auto array (on stack) of variable size. It can be used in a typedef statement. C supports variable-sized arrays from the C99 standard. For example, the below program compiles and runs fine in C.

Syntax of VLAs in C

void fun(int size)
{
     int arr[size];
     // code
}

Note: In C99 or C11 standards, there is a feature called flexible array members, which works the same as the above.

Example of Variable Length Arrays

The below example shows the implementation of variable length arrays in C program

C

// C program to demonstrate variable length array #include <stdio.h>  // function to initialize array void initialize(int* arr, int size) {     for (int i = 0; i < size; i++) {         arr[i] = i + 1;     } }  // function to print an array void printArray(int size) {     // variable length array     int arr[size];     initialize(arr, size);      for (int i = 0; i < size; i++) {         printf("%d ", arr[i]);     } }  // driver code int main() {     int n;     printf("Enter the Size: ");     scanf("%d", &n);     printArray(n);      return 0; }

Output

Enter the Size: 5
1 2 3 4 5

Explanation: The above program illustrate how to create a variable size array in a function in C program. This size is passed as parameter and the variable array is created on the stack memory.

What are the data types for which it is not possible to create an array?

A

Abhay Rathi and Sanjay Kanna

Improve

Article Tags :

C Language
C++
C Array and String
cpp-array

Practice Tags :

CPP

Similar Reads

An array in C is a fixed-size collection of similar data items stored in contiguous memory locations. It can be used to store the collection of primitive data types such as int, char, float, etc., and also derived and user-defined data types such as pointers, structures, etc. Array DeclarationIn C,

Properties of Array in C

An array in C is a fixed-size homogeneous collection of elements stored at a contiguous memory location. It is a derived data type in C that can store elements of different data types such as int, char, struct, etc. It is one of the most popular data types widely used by programmers to solve differe

Length of Array in C

The Length of an array in C refers to the maximum number of elements that an array can hold. It must be specified at the time of declaration. It is also known as the size of an array that is used to determine the memory required to store all of its elements. In C language, we don't have any pre-defi

Multidimensional Arrays in C - 2D and 3D Arrays

A multi-dimensional array in C can be defined as an array that has more than one dimension. Having more than one dimension means that it can grow in multiple directions. Some popular multidimensional arrays include 2D arrays which grows in two dimensions, and 3D arrays which grows in three dimension

Initialization of Multidimensional Array in C

In C, multidimensional arrays are the arrays that contain more than one dimensions. These arrays are useful when we need to store data in a table or matrix-like structure. In this article, we will learn the different methods to initialize a multidimensional array in C. The easiest method for initial

Jagged Array or Array of Arrays in C with Examples

Prerequisite: Arrays in CJagged array is array of arrays such that member arrays can be of different sizes, i.e., we can create a 2-D array but with a variable number of columns in each row. These type of arrays are also known as Jagged arrays. Example: arr[][] = { {0, 1, 2}, {6, 4}, {1, 7, 6, 8, 9}

Pass Array to Functions in C

Passing an array to a function allows the function to directly access and modify the original array. In this article, we will learn how to pass arrays to functions in C. In C, arrays are always passed to function as pointers. They cannot be passed by value because of the array decay due to which, wh

How to pass a 2D array as a parameter in C?

A 2D array is essentially an array of arrays, where each element of the main array holds another array. In this article, we will see how to pass a 2D array to a function. The simplest and most common method to pass 2D array to a function is by specifying the parameter as 2D array with row size and c

How to pass an array by value in C ?

In C programming, arrays are always passed as pointers to the function. There are no direct ways to pass the array by value. However, there is trick that allows you to simulate the passing of array by value by enclosing it inside a structure and then passing that structure by value. This will also p

Variable Length Arrays (VLAs) in C

In C, variable length arrays (VLAs) are also known as runtime-sized or variable-sized arrays. The size of such arrays is defined at run-time. Variably modified types include variable-length arrays and pointers to variable-length arrays. Variably changed types must be declared at either block scope o

Corporate & Communications Address:

A-143, 7th Floor, Sovereign Corporate Tower, Sector- 136, Noida, Uttar Pradesh (201305)

Registered Address:

K 061, Tower K, Gulshan Vivante Apartment, Sector 137, Noida, Gautam Buddh Nagar, Uttar Pradesh, 201305

Advertise with us

Company
About Us
Legal
Privacy Policy
In Media
Contact Us
Advertise with us
GFG Corporate Solution
Placement Training Program

Languages
Python
Java
C++
PHP
GoLang
SQL
R Language
Android Tutorial
Tutorials Archive

DSA
Data Structures
Algorithms
DSA for Beginners
Basic DSA Problems
DSA Roadmap
Top 100 DSA Interview Problems
DSA Roadmap by Sandeep Jain
All Cheat Sheets

Data Science & ML
Data Science With Python
Data Science For Beginner
Machine Learning
ML Maths
Data Visualisation
Pandas
NumPy
NLP
Deep Learning

Web Technologies
HTML
CSS
JavaScript
TypeScript
ReactJS
NextJS
Bootstrap
Web Design

Python Tutorial
Python Programming Examples
Python Projects
Python Tkinter
Python Web Scraping
OpenCV Tutorial
Python Interview Question
Django

Computer Science
Operating Systems
Computer Network
Database Management System
Software Engineering
Digital Logic Design
Engineering Maths
Software Development
Software Testing

DevOps
Git
Linux
AWS
Docker
Kubernetes
Azure
GCP
DevOps Roadmap

System Design
High Level Design
Low Level Design
UML Diagrams
Interview Guide
Design Patterns
OOAD
System Design Bootcamp
Interview Questions

Inteview Preparation
Competitive Programming
Top DS or Algo for CP
Company-Wise Recruitment Process
Company-Wise Preparation
Aptitude Preparation
Puzzles

School Subjects
Mathematics
Physics
Chemistry
Biology
Social Science
English Grammar
Commerce
World GK

GeeksforGeeks Videos
DSA
Python
Java
C++
Web Development
Data Science
CS Subjects

@GeeksforGeeks, Sanchhaya Education Private Limited, All rights reserved

We use cookies to ensure you have the best browsing experience on our website. By using our site, you acknowledge that you have read and understood our Cookie Policy & Privacy Policy

Improvement

Suggest Changes

Help us improve. Share your suggestions to enhance the article. Contribute your expertise and make a difference in the GeeksforGeeks portal.

geeksforgeeks-suggest-icon

Create Improvement

Enhance the article with your expertise. Contribute to the GeeksforGeeks community and help create better learning resources for all.

geeksforgeeks-improvement-icon

Suggest Changes

min 4 words, max Words Limit:1000

Thank You!

Your suggestions are valuable to us.

What kind of Experience do you want to share?

Interview Experiences

Admission Experiences

Career Journeys

Work Experiences

Campus Experiences

Competitive Exam Experiences