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;
    for(len=0;str[len]!='\0';len++);

    int i;
    int sum=0;
    int mul = 1;
    //printf("%d",len);
    for(i=len-1;i>=0;i--){
        if(str[i] == '1' ){
            //printf("hi");
            sum += mul;
        }
        mul *= 2;
    }

    return sum;
}

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

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

Solving Approach