Module 4: Arrays

Array

A collection of data items, all of the same type, accessed using a common name.

One-dimensional array

An array that is like a list, where elements are accessed via a single index.

Two-dimensional array

An array that is like a table, where elements are accessed via two indices.

Vector

A one-dimensional array.

Matrix

A two-dimensional array.

Declaration of an array

dataType arrayName[arraySize];

Uninitialized arrays

Must have dimensions of their rows, columns, etc. listed within square brackets.

Array Index

A non-negative integer used to access elements of an array; starts from zero.

Initialize an array

To assign values to an array at the time of declaration using curly braces.

Accessing array elements

To retrieve or manipulate values in an array using indices.

Multidimensional array

An array that has more than one dimension, such as 2D or 3D.

Accessing 2D array elements

Use two subscripts, typically denoting row and column indices.

C++ array initialization

Arrays can be initialized at the time of declaration using brackets and values.

Array size

The number of elements an array can hold, which is fixed after declaration.

Common mistake with arrays

Forgetting that the first index starts at zero.

Floating-point array declaration

float mark[5]; // An array that can hold 5 floating-point values.

Example of a 3D array declaration

int threedim[5][10][4]; // A three-dimensional array.

Array of arrays

A way to conceptualize multidimensional arrays, where each element is an array.

Partial array initialization

Initializing some elements of an array while leaving others as zero.

Constant expressions for array dimensions

Dimensions used in C++ arrays must be positive integral constants or constant expressions.

Input and output of array elements

Using scanf and printf functions to take input and print elements of an array.