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What is Array? Definition, Types & Usage

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5th Nov, 2021
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What is Array? Definition, Types & Usage

An array is a collection of homogeneous elements stored in a contiguous memory location for better access and easier calculation by the system. Contrary to scalar variables, an array contains a sequence of multiple elements that may range from text, integers, or even other sets of arrays. Arrays are beneficial for constructing and solving groups of various values that require similar action. Instead of manually sorting information to initiate computing processes, array creation transforms a lengthy process into a convenient one.

Imagine your favourite book as an array and the chaptered pages as its containing elements. They form a group of similar items that can be easily sorted by finding its index expression, the chapter number. Arrays are indexed using a specific sequence number to maintain the arrangement and accessibility of the element. This sequence number helps find specific array elements to obtain information.

Arrays play a significant role in indexing data for programming as the process deals with heaps of related and unrelated data. It avoids the usage of lengthy variables to replace with relevant sorted value sequences. An array can hold multiple finite values referred by a single name but indexes different values of varying elements in the memory. 

Types of Arrays

The convenient process of collecting data in a grouped form can be done through diverse types of array, which are as follows.

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1. Multidimensional Arrays

A multidimensional array is not limited to containing only integer or character values; it can also hold a completely separate array. Also known as the n-dimensional array, this format captures more than two aspects of an element in a tabular form containing multiple rows and columns. Multidimensional structures program multiple groups of information without the need to index numerous variables separately.

To understand it better, envision structuring the obtained number of marks for 45 students in 7 subjects. Instead of creating a declaration for each subject comprising 45 students, multidimensional arrays help with just one and index the values separately.

Use => int marks [7] [45]

Instead of => int S1 [45]

int S2 [45]

int S3 [45]

int S4 [45] 

2. Indexed Arrays 

Indexed arrays store elements in numeric indexes. Data elements are created against a certain numeric value that acts as its index, positioning the data in a unique place to look up their spot systematically. Indexed arrays are always initiated by 0 as the value of its first element. 

The ability to identify array elements through their position makes indexed arrays convenient as you don’t need to produce arrays in advance. They are automatically created subsequently as the syntax proceeds. Indexed arrays contain the index and key, clearly indicating the stored content of the accessed array.

3. Associative Arrays

Associative arrays use a set of strings instead of numeric values to determine the unique position of an array element and identify it simultaneously. This array format comprises pairs of keys and indexes used to access a unique string containing one value. Prominently, this array format is applied to seek the same indexed keys for values instead of codes.

For example, to recognise scores of students in a class, you can create a string of students’ names as keys and subject marks as values for easy reference. However, one of the major drawbacks of this approach is its inability to perform successfully in a loop due to the lack of a numeric value.

What is an Array in C Language?

A high-level programming language as C has to deal with enormous data to analyse and create the best possible outcomes. The role of arrays in the C language is significant considering it stores primitive data such as int, float, char, etc., in a structured collection. A system can easily access the contained elements by simply using index numbers. Array positively extends easy access to array data without needing to feed lengthy strings of codes. On the other hand, array focuses on simplifying implementation by strengthening the algorithms. While arrays extend numerous benefits, the lack of negative array indexes often makes the process extremely time-consuming. 

Advantages of Using Array

1. Compilation of data

Array constitutes multiple data elements in a single group using a single name, simplifying the process of accessing similar elements at one place.

2. Allocation of memory

Array places data in a consecutive form for all its containing data elements, leading to optimal memory allocation for all its elements. This saves data elements in an array from both memory shortage and overflow.

3. Supports multiple data types

The array supports multiple data types to represent a collection of data. Some of them include char, integer, float, numeric, binary, etc.

4. Rephrase data value

Array allows changing element data values without harming its unique position or the entire content of the array. If a programmer needs to change data value, the process includes no risk of losing element data.

5. Extends multiple sorting techniques

Array allows the usage of multiple sorting methods to assemble array elements, effectively extending the most suitable format in certain situations.

Disadvantages of Using Array

1. Fixed-size

Arrays are usually of a fixed size and do not allow deletion or addition of data. It contains a fixed number of single data type values. The length of an array becomes fixed once it is created.

2. No random access

Data elements cannot be randomly accessed. Reaching a particular record would need the programmer to input the detailed index.

3. Homogeneous nature

The homogenous nature of arrays often becomes a disadvantage as an array can only include values similar to each other. It cannot store differing data values.

4. Memory allocation

Allocating less memory than needed for an array may lead to data loss.

5. Limited functionality

Array may be an excellent data structure for uncomplicated projects, but complex problems require a more stable and functional data structure that can deal with diverse data values.

Application of Arrays

The purpose of arrays extends more than basic data collection and is implemented through several programming languages. Find its most dynamic applications as follows.

  • The ordered nature of arrays is used in multiple programming languages to manage, sort, analyse and use data.
  • Array permits execution of Matrices, one of the most important parts of programming languages’ mathematical library.
  • The core of nearly all sorting algorithms is created using arrays.
  • Arrays make the implementation of queues and stacks possible.
  • Algorithms used for CPU scheduling implement arrays.
  • Arrays help implement lists and vectors, a significant part of C++ STL.

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Arrays are one of the most widely used data structures, without which any programming arrangement is incomplete. Arrays perform well at places demanding sorted data layout through its convenient working process. The ordered list of elements greatly benefits the course of lengthy programming structures. However, complex data layouts are yet to be conquered by arrays which may receive an update in future to extend better results. 

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Pavan Vadapalli

Blog Author
Director of Engineering @ upGrad. Motivated to leverage technology to solve problems. Seasoned leader for startups and fast moving orgs. Working on solving problems of scale and long term technology strategy.

Frequently Asked Questions (FAQs)

1What is the biggest hurdle of using an array?

Array demands users to define its size beforehand. While creating a bigger sized array may lead to wastage of space, not allocating enough space can lead to deletion of excessive data. The only solution to tackling this problem is using dynamic or associative arrays.

2What is the difference between an array and a list?

An array is an assortment of similar types of data, while a list can include dissimilar data values. Both are used to store data and can be indexed, but only arrays can comprehend arithmetic operations, so they should be used over lists for relevant calculations.

3Why do we use Array?

Array is used to store a fixed collection of data variables of the same type. It simplifies the collection of complex data structures by creating fixed size boxes of similar variables for easy accessibility during system processes.