isupper() ctype Macro (ctype.h) isupper() Check if a character is an upper-case letter #include <ctype.h> int isupper(c) int c; isupper tests whether the argument c is an upper-case letter (A- Z). It returns a number other than zero if c is an upper-case letter, and zero if it is not. isupper assumes that c is an ASCII character or EOF. ***** Example ***** For an example of how to use this macro, see the entry for ctype. ***** See Also ***** ASCII, ctype COHERENT Lexicon Page 1