double my_accu_buf[SOME_PARTICULAR_INTEGER_SIZE];

double my_var = 0;  // ?

double darray[20];
Zero(darray);

#include <iostream>

int main() {
        double array[10];
        std::fill(std::begin(array), std::end(array), 0.0);

        for (int i = 0; i < 10; ++i) {
                std::cout << array[i] << "\n";
        }

        return 0;
}

#include <iostream>
#include <array>

int main() {
        std::array<double, 10> array;
        array.fill(0.0);

        for (auto d : array) {
                std::cout << d << "\n";
        }

        return 0;
}

double* array_ptr = new double[some_calculated_size];

Buffer<double> darray(200, 0.0);

for(int i = 0; i < 200; i++)
  Cout() << darray[i] << "\n";