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) {
    // Your logic here

    if(num == 0){
            printf("0");
            return;
        }
    if(base == 2){
        uint16_t mask = 1U << 15;
        int counter = 0;

        //remove padding zeros
        

        while((mask & num) == 0){
            mask = mask >> 1;
            counter ++;
        }
        for(int i = 0; i< 16-counter; i++){
            printf("%d", ((num&mask) != 0));
            mask = mask >> 1;
        }
        return;
    }

    // base 16
    uint16_t mask = 0xF000;
    int counter = 0;

    while( (mask & num) == 0){
        mask = mask >> 4;
        counter ++;
    }
    
    for( int i = counter; i< 4; i++){
        uint16_t val = num&mask;
        val = val >> 4*(3-counter);
        mask = mask >> 4;
        counter ++;

        // printf("val: %d\n", val);
        if(val <= 9){
            printf("%d", val);
        }else{
            printf("%c", 'A'+(val-10));
        }
    }
}

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

    print_base(num, base);
    return 0;
}

Solving Approach