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) {
    // Your logic here
    int len = 0 ;
    const char *tmp = str;
    uint16_t res = 0;

    while(*tmp)
    {
        len++;
        tmp++;
    }

    for(int n = 0 ; n < len ; n++)
    {
        if(str[len - n - 1] == '1')
        {
            res |= 1<<n;
        }
    }

    return res;
}

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

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

Solving Approach