Introduction to Arrays - Organizing Multiple Values Efficiently

Vaibhav • September 9, 2025

When writing programs, you often need to store multiple values of the same type. While individual variables work, they quickly become cumbersome when you have many values. This is where arrays come in - a simple, fixed-size, indexed collection of elements of the same type. Arrays help organize data efficiently, make code more readable, and give direct access to values using an index.

What is an Array?

An array is essentially a sequence of elements stored consecutively in memory. All elements must be of the same type, for example, integers, strings, or booleans. Arrays are **zero-indexed in C#**, meaning the first element is at index 0, the second at index 1, and so on.

// Declaring an array of 5 integers
int[] numbers = new int[5];

// Accessing elements
numbers[0] = 10;
numbers[1] = 20;
Console.WriteLine(numbers[0]); // Output: 10

Explanation: Here, numbers is an array of five integers. We can access each element using its index. Arrays are fixed-size, so you cannot add a sixth element without creating a new array.

Arrays vs Variables

Imagine you need to store the scores of five students. You could create five separate variables:

int score1 = 85;
int score2 = 90;
int score3 = 78;
int score4 = 92;
int score5 = 88;

But this quickly becomes messy, especially if you want to process all scores in a loop. With an array:

int[] scores = {85, 90, 78, 92, 88};
Console.WriteLine(scores[2]); // Access third student's score: 78

Using an array makes your code compact, readable, and easier to maintain. You can iterate over it, sort it, or pass it to methods efficiently.

How Arrays Are Stored in Memory

Understanding how arrays are stored can help you grasp why they are fast and why certain operations are efficient:

• Arrays occupy a contiguous block of memory, meaning all elements are placed one after another in RAM.
• This arrangement allows the program to calculate the memory address of any element quickly. For example, numbers[3] doesn’t require scanning previous elements - the address is computed directly.
• This is why array access by index is constant time (O(1)).
• However, arrays have a fixed size, so resizing requires creating a new array and copying elements over.

Why Arrays Matter

Arrays are a foundational data structure in programming because they allow:

• Efficient storage: All elements of the same type are stored together, reducing memory overhead.
• Direct access: You can retrieve or update any element quickly using its index.
• Iteration and computation: Loops can process array elements systematically.
• Basis for more advanced structures: Collections, lists, matrices, and even more complex data structures rely on arrays internally.

Basic Syntax Overview

Declaring an array in C# follows this pattern:

type[] arrayName = new type[size];

Example:

int[] numbers = new int[5];   // array of 5 integers
bool[] flags = new bool[3];       // array of 3 boolean values
string[] names = new string[4];   // array of 4 strings

You can also declare and initialize in one line:

int[] primes = {2, 3, 5, 7, 11};
string[] fruits = {"Apple", "Banana", "Mango"};

Summary

Arrays are fixed-size, indexed collections that store elements of the same type in a contiguous block of memory, enabling fast access and efficient processing. They are essential for organizing multiple values, iterating over data, and forming the foundation for more advanced collections and data structures. In the next article, we will explore how to declare, initialize, and populate arrays in detail, including default values and partial initialization, while continuing to build your understanding of arrays as a core programming concept.