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
  uint16_t num = 0;

  while(*str != '\0'){
    num = num << 1; //multiply by 2
    if(*str == '1'){
        num += 1; ////add 1 iff bit is 1
    } else if(*str != '0'){
        return 0; ///return 0 if find invalid char
    }
    str++;
  }
  return num;
}

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

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

Solving Approach