Convert Binary String to Integer Without strtol function or Libraries

Code

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

uint16_t binary_to_uint(const char *str) {
    uint16_t Number = 0;
    uint16_t len = 0;
    while( str[len] != '\0'){
        len++;
    }

    int digit = 1;
    for(int i = len; i > 0; i--){
        if(str[i - 1] == '1') {
            Number += digit;
        }
        digit *= 2;
    }
    return Number;
}

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

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

Solving Approach