C ctype (ctype.h) Library
C ctype Functions
The <ctype.h> header provides many functions for classifying and
modifying characters.
| Function | Description |
|---|---|
| isalnum() | Checks whether a character is alphanumeric |
| isalpha() | Checks whether a character is a letter |
| isblank() | Checks whether a character is a space or tab |
| iscntrl() | Checks whether a character is a control character |
| isdigit() | Checks whether a character is a decimal digit |
| isgraph() | Checks whether a character has a graphical representation |
| islower() | Checks whether a character is a lowercase letter |
| isprint() | Checks whether a character is a printable character |
| ispunct() | Checks whether a character is a punctuation character |
| isspace() | Checks whether a character is a whitespace character |
| isupper() | Checks whether a character is an uppercase letter |
| isxdigit() | Checks whether a character is a hexadecimal digit |
| tolower() | Returns a lowercase version of a character |
| toupper() | Returns an uppercase version of a character |