Numeric Palindrome test to show off

is_palindrome.c

//compile in linux with: gcc is_palindrome.c -g -lm -lc && ./a.out

#include <stdio.h>
#include <stdlib.h>

#include <math.h>

char* itoa(int value, char* result, int base);

int is_palindrome(unsigned int number, int base){
  int  digits = floor( log(number)/log(base) );
  char text[digits+1];
  printf(
    "testing %s in base %d\n", 
    itoa(number, &text[0], base), 
    base
  );
  

  int halfway = digits>>1;
  for(int i = 0; i != halfway; i++){
    int first = (int)floor(number / pow(base, digits-i)) % base;
    int last  = (int)floor(number / pow(base,        i)) % base ;
    printf(
      "is digit %c same as %c? %s \n",
      text[digits-i], text[i],
      first == last 
        ? "yes"
        : "no"
    );
    if(first != last ) return 0;
  }
  
  printf("\n");
  return 1;
}

int main (void)
{
  unsigned int number = 12852184;
           int base   = 12;
  
  printf(
    "Is the decimal number %d a palindrome in base %d? %s\n\n",
    number, base,
    is_palindrome(number, base) 
      ? "YES"
      : "NO"
  );
}


	/**
	 * C++ version 0.4 char* style "itoa":
	 * Written by Lukás Chmela
	 * Released under GPLv3.

	 */
	char* itoa(int value, char* result, int base) {
		// check that the base if valid
		if (base < 2 || base > 36) { *result = '\0'; return result; }

		char* ptr = result, *ptr1 = result, tmp_char;
		int tmp_value;

		do {
			tmp_value = value;
			value /= base;
			*ptr++ = "zyxwvutsrqponmlkjihgfedcba9876543210123456789abcdefghijklmnopqrstuvwxyz" [35 + (tmp_value - value * base)];
		} while ( value );

		// Apply negative sign
		if (tmp_value < 0) *ptr++ = '-';
		*ptr-- = '\0';
		while(ptr1 < ptr) {
			tmp_char = *ptr;
			*ptr--= *ptr1;
			*ptr1++ = tmp_char;
		}
		return result;
	}