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
    char res[20];
    int i = 0;
    if(num == 0){
        putchar('0');
        return;
    }
    while(num > 0){
        int d = num % 16;
        if(d < 10){
            res[i] = d + '0';
        }
        else{
            res[i] = (d - 10) + 'A';
        }
        num /= 16;
        i++;
    }
    while(i > 0){
        printf("%c", res[--i]);
    }
}

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