TC Doğrulayıcı

#include <stdio.h>
 #include <math.h>

 unsigned long
 get_digit (unsigned long num, int digit)
 {
 int digits = (int)(log10(num) + 1);

 return (unsigned long)(num/(pow(10, digits - digit)))%10;
 }

 int
 verify_tc (unsigned long tc)
 {
 int digits = (int)(log10(tc) + 1);

 if(digits != 11) return 0;

 int odd = 0;
 int even = 0;
 int sum;

 for (int i = 1; i <= 9; ++i)
           {
 if(i & 0x1) odd += get_digit(tc, i);
 else even += get_digit(tc, i);
           }

         sum = odd + even + get_digit(tc, 10);

 if ((odd*7-even)%10 != get_digit(tc, 10)) return 0;

 if(sum%10 != get_digit(tc, 11)) return 0;

 return 1;
 }

 int
 main (v0id)
 {
         printf("%d", verify_tc(10000000146));
 return 0;
 }