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C Int, char validation functions:
There are many inbuilt functions in C language which are used to validate the data type of given variable and to convert upper to lower case and lower to upper case are given below with description and simple example programs.
List of inbuilt int, char validation functions in C programming language:
- “ctype.h” header file support all the below functions in C language. Click on each function name below for detail description and example programs.
| Functions | Description |
| isalpha() | checks whether character is alphabetic |
| isdigit() | checks whether character is digit |
| isalnum() | Checks whether character is alphanumeric |
| isspace() | Checks whether character is space |
| islower() | Checks whether character is lower case |
| isupper() | Checks whether character is upper case |
| isxdigit() | Checks whether character is hexadecimal |
| iscntrl() | Checks whether character is a control character |
| isprint() | Checks whether character is a printable character |
| ispunct() | Checks whether character is a punctuation |
| isgraph() | Checks whether character is a graphical character |
| tolower() | Checks whether character is alphabetic & converts to lower case |
| toupper() | Checks whether character is alphabetic & converts to upper case |