Convert Binary String to Integer Without strtol function or Libraries

Code

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

uint16_t binary_to_uint(const char *str) {
    uint16_t num = 0;
    int len = strlen(str);
    for (uint16_t i = 0; i < len; i++) {
        if (str[i] == '1') {
            num += (1 << (len - i - 1)); 
        }
    }
    return num;
}

int main() {
    char bin[20];
    scanf("%s", bin);

    printf("%u", binary_to_uint(bin));
    return 0;
}

Solving Approach