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) {
    int result = 0, len = 0;
    while(str[len++] != '\0');
    len--;
    for(int i = len - 1; i >= 0; i--){
        if(str[i] == '1'){
            result += (1U << len-i-1);
        }
    }
    return result;
}

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

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

Solving Approach