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 index=0;
    while(str[index]!='\0'){
        index++;
    }
    int num=0;
    for(int i=index-1;i>=0;i--){
        if(str[i]=='1'){
            num|=(1<<((index-1)-i));
        }
    }
    return num;
}

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

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

Solving Approach