Fixed-Size Arrays & Zero-Based Indexing
An array is a fixed-size collection of items of the same data type stored in contiguous memory. You access individual elements in O(1) instant time using their zero-based index: items[0], items[1].
"An array is like a row of numbered mailboxes outside a post office. Mailbox 0, Mailbox 1, Mailbox 2... Each box is identical in size and holds mail for one specific recipient."
Deep Dive: How It Works
Declaration: int[] scores = new int[5]; (creates an array of 5 integers, all defaulting to 0).
Initialization Literal: string[] names = { "Neo", "Trinity", "Morpheus" };.
Accessing & Modifying: names[0] = "Thomas"; reads and overwrites the first element.
Array Length (.Length): scores.Length returns the total number of elements.
Index from End (^1 in modern C#): names[^1] accesses the last element cleanly!
Syntax Blueprint
int[] nums = { 10, 20, 30 };
Console.WriteLine(nums[0]); // 10
nums[1] = 99; // Replaces 20 with 99
int count = nums.Length; // 3Array declaration, zero-based indexing, and .Length property.
Core Rules to Remember
Common Beginner Traps & How to Fix Them
Accessing arr[5] on an array of length 5 (new int[5])Why it happens: Forgetting that indices run from 0 to 4.
How to fix: Valid indices for length 5 are [0], [1], [2], [3], and [4].
Live Interactive Example
Hit Run Code to see it liveYour Turn: Micro Challenge
No pressure! Edit the starter code below and test your solution with instant feedback.
Find the largest number in an array
- Declare int[] numbers = { 15, 62, 38 };
- Find the maximum value and print "Max: 62".
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