| Function | Description |
|---|---|
| isalnum | checks if char is alphanumeric |
| isalpha | checks if char is alphabetic |
| isascii | checks if char is an ascii char |
| isblank | checks if char is blank |
| iscntrl | checks if char is a control char |
| isdigit | checks if char is a digit |
| isgraph | checks if char is printing character except space (' ') |
| islower | checks if char is lowercase |
| isprint | checks if char is printable |
| ispunct | checks if char is a punctuation char |
| isspace | checks if char is space |
| isupper | checks if char is uppercase |
| isxdigit | checks if char is hexadecimal |