C program to check whether a given number is Armstrong or not

Write a C program to check whether a given number is Armstrong or not.
If sum of nth power of digits of a number equals itself, then it is an Armstrong number.  Here, n represents the number of digits in a number.

Example:
153 = 1^3 + 5^3 + 3^3 =153
Here, power 3 represents the number of digits in the given input(153).

1634 = 1^4 + 6^4 + 3^4 + 4^4
Here, 4 represents the number of digits in the given input(1634).

  #include <stdio.h>
  int main() {
        int res = 0, data, mod, temp, digits = 0;
        printf("Enter your data:");
        scanf("%d", &data);
        temp = data;

        /* calculating no of digits in given input */
        while (data > 0) {
                mod = data % 10;
                data = data / 10;
                digits++;
        }

        data = temp;

        /* sum of nth power of digits */
        while (data > 0) {
                mod = data % 10;
                res = res + pow(mod, digits);
                data = data / 10;
        }

        if (res == temp)
                printf("Given number is an armstrong\n");
        else
                printf("Given number is not an armstrong number\n");
        return 0;
  }

Note:
gcc ex05.c -lm 
lm - linking math library for pow() function.

  Output:

  jp@jp-VirtualBox:~/$ gcc ex05.c -lm
  jp@jp-VirtualBox:~/$ ./a.out
  Enter your data:1634
  Given number is an armstrong