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

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

void print_hex(uint16_t num) {
    char hex[5];
    int i = 0;
    if(num == 0){
        putchar('0');
        return;
    }
    while(num>0){
        uint8_t digit = num%16;
        if(digit<10) hex[i++] = '0' + digit;
        else hex[i++] = 'A' + (digit-10);
        num/=16;
    }
    for(int j=i-1;j>=0;j--) putchar(hex[j]);
}

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