ArrayofStructures

Array of structures (AoS) is a data organization pattern in which an array’s elements are structures, allowing multiple records of the same type to be stored contiguously in memory. This concept appears in languages such as C and C++, as well as in other languages with similar data models, where a single array holds multiple instances of a record type.

Each element in an AoS is a structure containing several fields. Access to a particular record is done by indexing the array and then referencing the field, for example arr[i].field in C/C++. The exact syntax can vary by language, but the idea remains the same: you store a fixed set of related fields together for every record in the array.

Memory layout and performance are influenced by the AoS model. Elements are stored consecutively, which provides good locality of reference when iterating through records. This can simplify data management and improve performance for operations that process whole records sequentially. However, if only one field is needed across many records, an AoS may incur unnecessary data access compared to alternative layouts.

Common use cases include storing lists of entities such as employees, students, or products, where each record shares the same fields (for example, id, name, and salary). AoS also supports straightforward passing of a whole record to functions and easy initialization of a fixed-size dataset.

Alternatives include array of pointers to structures, which adds indirection and memory overhead, and structure of arrays (SoA), where each field is stored in its own separate array. SoA can offer performance benefits for certain vectorized or columnar workloads but requires different programming patterns.