C++: Dot Product

Create a function/use an in-built function, to compute the dot product, also known as the scalar product of two vectors. If possible, make the vectors of arbitrary length.

As an example, compute the dot product of the vectors [1, 3, -5] and [4, -2, -1].

If implementing the dot product of two vectors directly, each vector must be the same length; multiply corresponding terms from each vector then sum the results to produce the answer.

#include <iostream>
#include <numeric>

int main()
{
	int a[] = { 1, 3, -5 };
	int b[] = { 4, -2, -1 };

	std::cout << std::inner_product(a, a + sizeof(a) / sizeof(a[0]), b, 0) << std::endl;

	return 0;
}