Array
An array is a collection of elements stored in contiguous memory locations and identified by at least one array index.
Features of Arrays: 1. Homogeneity: All elements are the same type. 2. Fixed Size: Once allocated, standard arrays cannot change size. 3. Zero-Indexing: Most modern languages start counting at 0. 4. Multi-dimensionality: Arrays can store other arrays (matrices).
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🧒 Explain Like I'm 5
Think of an [array](/en/terms/array) like a row of lockers in a school hallway. Each locker is the same size and has a number (the index). If you know the number, you can go straight to that locker and see what's inside without having to check all the others first.
🤓 Expert Deep Dive
At the hardware level, an array is a block of contiguous memory. The address of an element A[i] is calculated as BaseAddress + i * ElementSize. This hardware-level alignment is what enables [CPU cache](/en/terms/cpu-cache) optimizations like prefetching. However, this same contiguousness makes insertions and deletions expensive (O(n)), as subsequent elements must be moved to maintain the order. For large-scale data, the tradeoff between O(1) access and O(n) modification is a central design decision.