C ctype.h header


The C <ctype.h> header declared several functions for classifying and mapping characters.Note all the arguments are ‘int’ type,the argument is further converted to unsigned int type for performing the operation.

The behavior of the function is affected by the locale setting of the compiler.The default locale of the compiler is the “C” locale.And this locale affect only the Latin Alphabet.

All the functions are declare below.

Character classification functions
isalnumTest if the character is alphanumeric
isalphaTest if the character is alphabetic
isblankTest if the character is blank
iscntrlTest if the character is control characters
isdigitTest if the character is digit
isgraphTest if the character is graphic
islowerTest if the character is lowercase
isprintTest if the character is printable
isspaceTest if the character is space
ispunctTest if the character is punctuation mark
isupperTest if the character is upper case
isxdigitTest if the argument is hexadecimal digit
Character case mapping functions
tolowerReturn the lower case of the argument
toupperReturn the upper case of the argument