Convert Decimal Number to Binary or Hex Without itoa function

Code

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


void print_base(uint16_t num, uint8_t base) {
    if (base < 2 || base > 16) return;
 if (num == 0) {
        printf("0");
        return;
    }

    char digits[] = "0123456789ABCDEF";
    char res[20];
    int idx = 0;
    while (num > 0){
        res[idx] = digits[num % base];
        ++idx;
        num = num/base;
    }

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

    
}

int main() {
    uint16_t num;
    uint8_t base;
    scanf("%hu %hhu", &num, &base);

    print_base(num, base);
    return 0;
}

Solving Approach