extern crate num_traits;
extern crate num_complex;

use num_complex::Complex64;

fn generic_scalar_product<T>(v: &[T], w: &[T]) -> T
where
    T: num_traits::Zero + std::ops::Mul<Output = T> + Copy
{
    let length = v.len();
    assert_eq!(length, w.len());

    // We initialise `sum` to a "zero" of type T
    // using the `zero` method provided by the `Zero` trait
    let mut sum = T::zero();
    for index in 0..length {
        sum = sum + v[index] * w[index];
    }
    sum
}

fn main() {
    // Complex
    let v: Vec<Complex64> = vec![Complex64 { re: 1.0, im: 0.0 }, Complex64 { re: 1.0, im: 0.0 }, Complex64 { re: 1.0, im: 0.0 }];
    let w: Vec<Complex64> = vec![Complex64 { re: 1.0, im: 0.0 }, Complex64 { re: 1.0, im: 0.0 }, Complex64 { re: 1.0, im: 0.0 }];
    assert_eq!(generic_scalar_product(&v, &w), Complex64 { re: 3.0, im: 0.0 });
}