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

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

void print_hex(uint16_t num) {
    char out[4];
    int index = 0;

    if (num == 0) {
        printf("0");
        return;
    }

    while (num > 0) {
        uint8_t n = num & 0xF;
        if (n < 10)
            out[index++] = '0' + n;
        else
            out[index++] = 'A' + (n - 10);
        num >>= 4;
    }

    for (int i = index - 1; i >= 0; i--) {
        printf("%c", out[i]);
    }
}

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