❮ C Examples Octal Binary Convert C Function Cosh ❯

C Library Function - `isxdigit()`

C Standard Library - <ctype.h>

Description

The C library function int isxdigit(int c) checks if the passed character is a hexadecimal digit.

int isxdigit(int c) parameter c is a single character.

Hexadecimal digits are typically represented by the numbers 0 to 9 and the letters A to F (or a to f), where A to F represent 10 to 15: 0 1 2 3 4 5 6 7 8 9 a b c d e f A B C D E F.

Declaration

Here is the declaration for the isxdigit() function.

int isxdigit(int c);

Parameters

c -- This is the character to be checked.

Return Value

If c is a hexadecimal digit, the function returns a non-zero integer value; otherwise, it returns 0.

Example

The following example demonstrates the use of the isxdigit() function.

#include <ctype.h>
#include <stdio.h>

int main() {
   char c = '5';
   int result;

   // Passing the character
   result = isxdigit(c); // result returns non-zero
   printf("%c passed to isxdigit() function result is: %d", c, isxdigit(c));
   printf("\n");  // New line
   c = 'M';

   // Non-hexadecimal digit as parameter
   result = isxdigit(c); // result is 0

   printf("%c passed to isxdigit() function result is: %d", c, isxdigit(c));

   return 0;
}

Let's compile and run the above program, which will produce the following result:

5 passed to isxdigit() function result is: 1
M passed to isxdigit() function result is: 0

Finding hexadecimal digits in a string:

#include<ctype.h>
#include<stdio.h>
int main()
{
    char str[]="123c@#run[oobe?";
    int i;
    for(i=0;str[i]!='\0';i++) {
        if(isxdigit(str[i])) {
            printf("%c is a hexadecimal digit\n",str[i]);
        }
    }
}