Computer Programming Arrays

Computer Programming Arrays – Definition, Examples & Types (C, Java, Python)

An array is a data structure that allows you to store multiple values of the same data type in a single variable. Instead of creating separate variables for each value, arrays help organize data efficiently.

Example:
Instead of:

int n1 = 10;
int n2 = 20;
int n3 = 30;

You can use:

int numbers[3] = {10, 20, 30};

What Is an Array?

An array is a collection of elements stored in contiguous memory locations, meaning values are placed one after another in memory.
Each element is accessed using an index, starting from 0 in most programming languages.

Key Features

• Stores multiple values of the same type
• Uses indices to access elements
• Fixed size in languages like C and Java
• Dynamic size in Python (list)

Arrays in Different Programming Languages

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Arrays in C

C uses the following syntax to declare an array:

Declaration

int marks[5];

Initialization

int marks[5] = {50, 60, 70, 80, 90};

Accessing Elements

printf("%d", marks[2]);  // Output: 70

Arrays in Java

Java treats arrays as objects.

Declaration

int[] marks = new int[5];

Initialization

int[] marks = {50, 60, 70, 80, 90};

Accessing Elements

System.out.println(marks[2]);  // Output: 70

Arrays in Python

Python does not have traditional arrays. Instead, it uses lists, which are more flexible.

Declaration & Initialization

marks = [50, 60, 70, 80, 90]

Accessing Elements

print(marks[2])  # Output: 70

Types of Arrays

1. One-Dimensional Array

A simple linear list of elements.

Example in C:

int nums[4] = {1, 2, 3, 4};

2. Multi-Dimensional Arrays

These are arrays within arrays (matrix-like structures).

Example: 2D Array in C

int matrix[2][2] = {
  {1, 2},
  {3, 4}
};

Example: Python List of Lists

matrix = [
    [1, 2],
    [3, 4]
]

Common Array Operations

Here are some typical operations performed on arrays:

1. Traversing

Access each element using a loop.

Example in Java:

for(int i=0; i<marks.length; i++){
    System.out.println(marks[i]);
}

2. Updating

marks[1] = 95;

3. Searching

Iterate to find a value.

Memory Representation

Arrays store their values in continuous memory blocks, which makes them fast for indexing but inflexible when changing size (in languages like C and Java).

Python lists, however, are dynamic and resize automatically.

Uses of Arrays

Arrays are used in:

• Storing student marks
• Managing lists of items
• Matrix operations
• Image and graphics processing
• Sorting and searching algorithms
• Storing string collections

Arrays are fundamental to data structures and algorithms.

FAQ

What is an array in programming?

An array is a data structure that stores multiple values of the same type using indices.

What is the index of the first element in an array?

In most languages like C, Java, and Python, array indexing starts at 0.

Can Python store arrays?

Python uses lists, which act like dynamic arrays.

What are multidimensional arrays?

Arrays of arrays, such as tables or matrices.

Can arrays store different data types?

Most languages require arrays to hold the same data type.
Python lists can hold mixed data types.