Question

I have a long integer (ie 10001000110…) and an array with double values (ie {.5,.76,.34,…}) and I would like to loop through the binary representation of my integer and multiply each each digit with its corresponding place in my array and add it all together (matrix multiplication):

so like: 1*.5+0*.76+0*.34…..

whats best way to do this in C?

Thanks

Answer 1

Something like this?

int n = n_doubles;
double result = 0.0;

while (n--) {
    if ((long_integer>>n)%2)
        result += doubles[n_doubles - n];
}