There are some predefined functions available in "ctype.h" library for analyzing the character input and converting them.
Analysis Functions
The character analysis functions are listed below −
Function | Checks whether entered character is |
---|---|
isalpha | An alphabet (or) not |
isdigit | A digit (or) not |
isspace Q | A space, a newline (or) tab |
ispunct ( | A special symbol (or) not |
islower | A lower case letter of alphabet |
isupper Q | An upper case letter of alphabet |
isalphanumeric | An alphabet/digit or not |
Converting Functions
The converting functions are listed below −
Function | Conversion |
---|---|
tolower() | Converts an upper case alphabet to lower case |
toupper Q | Converts a lower case alphabet to upper case |
Program
Following is the C program for character analysis and conversion functions which are used to test the character type −
#include <stdio.h> #include <ctype.h> main(){ char character; printf("Press any key digit or alphabet\n"); character = getchar(); if (isalpha(character) > 0) printf("The character is a letter."); else if (isdigit (character) > 0) printf("The character is a digit."); else printf("The character is not alphanumeric."); }
Output
When the above program is executed, it produces the following result −
Run 1: Press any key digit or alphabet 3 The character is a digit. Run 2: Press any key digit or alphabet G The character is a letter. Run 3: Press any key digit or alphabet & The character is not alphanumeric.