Memory Layout

Overview

Arrays store their elements in a single block of consecutive memory. This means each element is placed directly next to the previous one without any gaps. The layout gives arrays predictable structure and allows fast access to elements by their index.

Contiguous Memory

When an array is created, a continuous section of memory is reserved for all of its elements. Because the memory is grouped together, the computer can easily calculate the exact location of any element using the starting address of the array and the element's position.

Fast Index Access

Accessing an element by index is fast because its position is always at a fixed distance from the start of the array. The computer does not need to search or scan through the array. It jumps straight to the needed memory location using simple arithmetic.

Cost of Resizing

A fixed block of memory means an array cannot easily grow or shrink. If you need more space than the array was created with, a new larger memory block must be allocated and all existing elements must be copied into it. This makes resizing an expensive operation.

Why the Layout Matters

Understanding memory layout explains why some array operations are fast and others are slow. Reading an element by index is fast because of predictable memory positions. Operations that change array size are slower because they often require copying all elements to new memory.