#include <iostream>
using namespace std;

struct vector2d {

    vector2d(float y, float x) : y(y), x(x) {}
    vector2d() : y(-1), x(0) {}

    float y, x;
};

class Foo {

	public:
	    Foo() {
	        acceleration_force = vector2d();
	        //acceleration_force(); не видит конструктора вообще
	        std::cout << "acc x: " << acceleration_force.x << " y: " << acceleration_force.y << std::endl;
	    }
	private:
	    vector2d acceleration_force;
};

int main() {
	std::cout << "begin" << std::endl;
	Foo foo = Foo();
	return 0;
}