Convert Integer to Hex String Without sprintf or itoa functions

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

void print_hex(uint16_t num) {
    // Buffer for up to 4 hex digits (+1 for '\0' if needed)
    char buf[5];
    
    // Special case for zero
    if (num == 0) 
        putchar('0');
        
    int i = 0;
    // Extract hex digits (from LSB)
    while (num > 0) 
    {
        uint8_t digit = num % 16;
        if (digit < 10)
            buf[i] = '0' + digit;
        else
            buf[i] = 'A' + (digit - 10);
        num /= 16;
        i++;
    }
    
    // Print in reverse order (from MSB)
    for (int j = i - 1; j >= 0; j--)
        putchar(buf[j]);
}

int main() {
    uint16_t num;
    scanf("%hu", &num);
    print_hex(num);
    return 0;
}