Convert Integer to Hex String Without sprintf or itoa functions

Code

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

void print_hex(uint16_t num) {
    // Your logic here
    char buff[5];
    int idx = 0;
    if(num == 0){
        printf("0");
    } else {
        
        while(num > 0){
            uint16_t digit = num % 16;
            if(digit >=0 && digit <= 9){
                buff[idx++] = '0' + digit;
            }else if(digit >= 10 && digit <= 15){
                buff[idx++] = 'A' + (digit - 10);
            }
            num /= 16;
        }
        buff[idx] = '\0';
    }

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

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

Solving Approach