How Many Types of Array

Introduction

Arrays can be defined in two ways, one concerning computing and the other for mathematics. In computing, an array can be defined as a collection of the same type integer, strings or characters placed in contiguous memory locations that can be individually referenced by using an index to a unique identifier. In mathematics, an array refers to a set of numbers or objects that are bound to follow a specific pattern. An array is an orderly arrangement often in the form of rows, columns or a matrix. These arrangements are mainly used as a visual tool for demonstrating multiplication and division.

Arrays in Computer Science

An array is a data structure that holds data that is similar and related. An array can be explained as a collection of boxes, where each one is called an element. Each element has a location in the array and can hold a value. The data in the array must be of the same data kind. An array is stored such that the position of each element can be computed from its index tuple through a mathematical formula.

Declaring an array

An array must be announced before it can be used. To announce an array a programmer gives it at least two properties - An identifier and size (the number of elements it will hold)

For example, in Visual Basic:

Dim score (9) As Integer - this would declare an array with ten elements (0 - 9), where each element would store an integer. Once declared, the name and structure of an array can not be changed. It is possible to indicate an array without positioning the size first. This is called a dynamic array. To use a dynamic array, data must be added up to the last of the array, or a new size must be set each time more data is attached.

In pseudo-code, proclaiming an array before use is not needed.

Types of Arrays in Computer Science

There are two types of arrays in computer science. They are -

One-dimensional array - this array is the simplest form of an array in which the elements are kept linearly and can be approached individually by specifying the index value of each element kept in the array. If the size is proclaimed to be 10, programmers can keep 10 elements. An array index always starts at 0. For example, if an array variable is declared as 10, then it ranges from 0 to 9. Each array element is kept in a separate memory position.

Multi-dimensional array - this is an array with more than one degree or dimension. For example, a 2D array, or two-dimensional array, is an array of arrays, which means it is a matrix of rows and columns. A 3D array attaches another dimension, turning it into an array of arrays of arrays.

Arrays in Mathematics

In mathematics, an "array" refers to a set of numbers or objects that will follow a specific pattern. There are many examples of arrays that help with understanding the utility of these tools for quick data analysis and simple multiplication or division of large groups or objects.

Arrays in Multiplication

When arrays in multiplication are being explained, the arrays are often referred to by the factors being multiplied. For example, an array of 49 balls arranged in seven columns of seven rows of balls would be described as a 7 by 7 array.

Arrays in Division

In division, arrays can be used as a handy tool to visually describe how large groups of objects can be divided equally into smaller groups. For example, 22 balls are asked to be divided into equal-sized groups to form an array as a guide to the division of balls. If asked to divide the balls equally among 11 students, for example, the class would produce an 11 by 2 array, demonstrating that each student would receive two balls if the 22 were divided equally among the 11 individuals.

Application

Arrays are used to implement mathematical vectors and matrices, as well as other kinds of rectangular tables. Many databases, small and large, include one-dimensional arrays whose elements are records.

Array-based implementations of data structures are frequently simple and space efficient, requiring little overhead, but may have poor space complexibility, particularly when modified, compared to tree-based data structures.

One or more large arrays are sometimes used to imitate in-program dynamic memory granting, particularly memory pool allocation.

Arrays can be used to determine a limited or complete control run in programs as a compact alternative to multiple “IF” statements. They are known in this context as "control tables" and are used in concurrence.

Notes

Arrays help maintain large sets of data under a single variable name to avoid confusion that can occur when using several variables. An array that is formed is homogeneous.