100% working C programming

include

include

include

include

include

include

include

include

void to_base(int n, int k, char *result) {

int index = 0;

while (n > 0) {
    int remainder = n % k;
    result[index++] = (remainder < 10) ? (remainder + '0') : (remainder - 10 + 'a');
    n /= k;
}
result[index] = '\0';

int len = strlen(result);
for (int i = 0; i < len/2; ++i) {
    char temp = result[i];
    result[i] = result[len - 1 - i];
    result[len - 1 - i] = temp;
}

}

int is_palindroms(const char *str) {

int len = strlen(str);
for (int i = 0; i < len/2; ++i) {

    if (str[i] != str[len - 1 - i]) {
        return 0;
    }
}
return 1;

}

int main() {

int n, k;
scanf("%d %d", &n, &k);

int sum = 0;
char base_k[64];

for (int i = 1; i <= n; ++i) {
    char decimal_str[64];
    sprintf(decimal_str, "%d", i);

    if (is_palindroms(decimal_str)) {
        to_base(i, k, base_k);

        if (is_palindroms(base_k)) {
            sum += i;
        }
    }
}
printf("%d\n", sum);
/* Enter your code here. Read input from STDIN. Print output to STDOUT */    
return 0;

}