specialcase

A special case is a particular instance that is treated differently from a general rule because of its unique characteristics. The term is used across disciplines to denote an exception or condition that requires separate consideration.

In mathematics, a problem’s special case is an instance where the general solution reduces to a simpler form or where standard assumptions fail, requiring a distinct derivation. For example, certain identities simplify when an angle takes a value such as zero or pi.

In computing, special-case handling refers to code paths that address inputs or conditions that do not fit the typical case. This can improve correctness and performance for rare inputs, but overuse can complicate software and conceal bugs. Good practice emphasizes robust general solutions with explicit testing for known edge cases.

In law and policy, special cases are exemptions or modifications to the general rule granted to particular individuals or situations. Such exceptions are usually codified and justified by safety, fairness, or practicality considerations.

The term may appear as "special case," "special-case," or as a compound in programming contexts, such as SpecialCase. It is often discussed alongside edge cases and exceptions to highlight deviations from the norm.

See also: edge case; exception; edge-case handling.