120. Convert Integer to Hex String Without sprintf or itoa functions

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

void print_hex(uint16_t num) {
    // Your logic here
    if(num == 0){
        putchar('0');
        return;
    }

    char digits[17] = "0123456789ABCDEF";
    char buf[20];
    int i = 0;
    while(num > 0){
        buf[i++] = digits[num % 16];
        num /= 16;
    }
    buf[i] = '\0';
    for(int j = i - 1; j >= 0;j--){
        putchar(buf[j]);
    }
}

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