Using functions isdigit, isalpha, isalnum, and isxdigit : char function « Data Type « C Tutorial

1. C Tutorial
2. Data Type
3. char function

#include <stdio.h>
#include <ctype.h>
 
int main()
{ 
   printf( "%s\n%s%s\n%s%s\n\n", "According to isdigit: ",
       isdigit( '8' ) ? "8 is a " : "8 is not a ", "digit",
       isdigit( '#' ) ? "# is a " : "# is not a ", "digit" );

   printf( "%s\n%s%s\n%s%s\n%s%s\n%s%s\n\n", 
       "According to isalpha:",
       isalpha( 'A' ) ? "A is a " : "A is not a ", "letter",
       isalpha( 'b' ) ? "b is a " : "b is not a ", "letter",
       isalpha( '&' ) ? "& is a " : "& is not a ", "letter",
       isalpha( '4' ) ? "4 is a " : "4 is not a ", "letter" );

   printf( "%s\n%s%s\n%s%s\n%s%s\n\n", 
       "According to isalnum:",
       isalnum( 'A' ) ? "A is a " : "A is not a ", 
       "digit or a letter",
       isalnum( '8' ) ? "8 is a " : "8 is not a ", 
       "digit or a letter",
       isalnum( '#' ) ? "# is a " : "# is not a ", 
       "digit or a letter" );

   printf( "%s\n%s%s\n%s%s\n%s%s\n%s%s\n%s%s\n", 
       "According to isxdigit:",
       isxdigit( 'F' ) ? "F is a " : "F is not a ", 
       "hexadecimal digit",
       isxdigit( 'J' ) ? "J is a " : "J is not a ", 
       "hexadecimal digit",
       isxdigit( '7' ) ? "7 is a " : "7 is not a ", 
       "hexadecimal digit",
       isxdigit( '$' ) ? "$ is a " : "$ is not a ", 
       "hexadecimal digit",
       isxdigit( 'f' ) ? "f is a " : "f is not a ", 
       "hexadecimal digit" );

   return 0;

}

According to isdigit:
8 is a digit
# is not a digit

According to isalpha:
A is a letter
b is a letter
& is not a letter
4 is not a letter

According to isalnum:
A is a digit or a letter
8 is a digit or a letter
# is not a digit or a letter

According to isxdigit:
F is a hexadecimal digit
J is not a hexadecimal digit
7 is a hexadecimal digit
$ is not a hexadecimal digit
f is a hexadecimal digit