#include <iostream>

using namespace std;

template <size_t S> double product(auto (&array)[S]) {
    double value = 1;
    for (auto &element: array) {
        value *= element;
    }
    return value;
}

int main() {
    float array[5] = {1, 2, 3, 5, 7};
    cout << product(array);
}