118. Convert Binary String to Integer Without strtol function or Libraries

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

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

uint16_t binary_to_uint(const char *str) {
    // Your logic here
    int i=0;
    uint16_t retval = 0;
    for(int i=(str_len(str) -1); i>=0; i--)
    {
        retval += (str[i] - '0') * (1<<(str_len(str) - i -1));
    }
    return retval;
}

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

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