Question

I’m trying to implement an Euclidean vector for my programming assignment. I need to overload operator* to provide dot product calculation for two vectors with arbitrary same dimension.
As 3D vector for example:

Vector<3> v1, v2; //two 3D vectors.

double dotProduct = v1 * v2;

The value of dotProduct should be v1[0]*v2[0]+v1[1]*v2[1]+v1[2]*v2[2]

So, my problem is how to get this value without using any explicit loop and std::accumulate() operation in numeric.h header file? Because those are forbidden in this assignment.

P.S. I may use functor(self defined) together with STL algorithm.

Answer 1

If you really want to avoid explicit loops and algorithms in general (not just std::accumulate), you could use std::valarrays instead:

std::valarray<double> a;
std::valarray<double> b;

// code to put data in a and b goes here

double dotProduct = (a * b).sum();

I’ve used double as the type here, but you can (of course) use whatever type makes sense for the data/situation you’re dealing with.