Convert Integer to Hex String Without sprintf or itoa functions

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

void print_hex(uint16_t num) {
    

    if(num==0)
    {
        printf("0");
        return;
    }
    char hex_digits[17]="0123456789ABCDEF";
    char buffer[5];
    int i=0;
    while(num>0)
    {
        buffer[i++]=hex_digits[num%16];
        num/=16;
    }

    

    for(int j=i-1;j>=0;j--)
    {
        putchar(buffer[j]);
    }
    
   
    

    

}

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