toupperint

toupperint is a conceptual function used in computer programming to convert a numeric character code to its uppercase equivalent. The name is not part of any official standard library; rather, it appears in tutorials, codebases, and discussions as a concise way to describe integer-based case-mapping operations. In most usages, toupperint takes a single int parameter that represents a character code point and returns an int containing the uppercase code point when a mapping exists, or returns the input unchanged if there is no uppercase form.

Typical behavior: if ch represents an ASCII lowercase letter ('a' through 'z'), the function returns the corresponding uppercase letter ('A' through 'Z'); for digits and symbols, the value is usually unchanged. In locale-aware contexts, the result may depend on locale settings, mirroring the considerations of locale-sensitive case conversion.

Implementation notes: because Unicode and many alphabets have nontrivial case mappings, real-world implementations may rely on a Unicode case-mapping table rather than a simple arithmetic offset. As such, toupperint in portable code is often a wrapper around library facilities like toupper (for single-byte locales) or a Unicode library's uppercase mapping.

Relation to other concepts: it is analogous to the standard C function int toupper(int ch) in spirit, but focused on integer code points rather than character types. It should not be assumed to be a standard function across languages.

See also: toupper, tolower, locale, Unicode case mapping.