Hi guys, Im a C beginner..so the questions I got for my submission is to find the magnitude of a vector ||X||

where:

X = [ 2 3 4 4 6 12]

I know ||X|| = sqrt(2^2+3^2+4^2+4^2+6^2+12^2)

but I have no idea where to start, my lecturer gave me a header:

double length(double a[], int n)

can somebody help me?

thank you soo much