C program for testing the character type

C Server Side Programming Programming

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 −

Live Demo

#include <stdio.h>
#include <ctype.h>
main(){
   char character;
   printf("Press any key digit or alphabet
");
   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.