Convert Integer to Hex String Without sprintf or itoa functions

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

void print_hex(uint16_t num) {
    char buffer[30];
    int i = 0;
    if(num == 0){
        printf("0");
        return;
    }
    while(num != 0){
        uint16_t rem = num % 16;
        if(rem >= 10 && rem <= 15){
            rem = (rem-10) + 'A';
            buffer[i] = rem;
        }else if(rem >= 0 && rem <= 9){
            buffer[i] = rem + '0';
        }
        num /= 16;
        i++;
    }
    for(int j=i-1; j>=0; j--){
        printf("%c",buffer[j]);
    }
    
}

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