Convert Binary String to Integer Without strtol function or Libraries

Code

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

uint16_t binary_to_uint(const char *str) 
{
    int decimal=0;
    int len=strlen(str);
    for(int i=0; i<len; i++)
    {
        if(str[i] == '1')
        {
            decimal=decimal+pow(2,len-1-i);
        }
    }
    return decimal;
}

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

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

Solving Approach