Convert Decimal Number to Binary or Hex Without itoa function

#include <stdio.h>
#include <stdint.h>

void print_base(uint16_t num, uint8_t base) {
    // Buffer to hold digits (max 16 bits → 16 binary digits + null terminator)
    char buffer[33];
    int index = 0;

    // Special case for 0
    if (num == 0) {
        printf("0\n");
        return;
    }

    while (num > 0) {
        uint8_t digit = num % base;
        if (digit < 10)
            buffer[index++] = '0' + digit;   // 0–9
        else
            buffer[index++] = 'A' + (digit - 10); // A–F for hex
        num /= base;
    }

    // Digits are stored in reverse order, so print backwards
    for (int i = index - 1; i >= 0; i--) {
        putchar(buffer[i]);
    }
    putchar('\n');
}

int main() {
    uint16_t num;
    uint8_t base;
    scanf("%hu %hhu", &num, &base);
    print_base(num, base);
    return 0;
}