Convert Binary String to Integer Without strtol function or Libraries

Code

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

uint16_t binary_to_uint(const char *str) {
    int l=strlen(str);
    int i,j=1,sum=0;
    for(i=l-1;i>=0;i--){
        if(str[i]=='1')
        sum=sum+j;
        j=j*2;
    }
    return sum;
}

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

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

Solving Approach