What will be the output of the program?

#include <iostream>
using namespace std;
class Animal {
public:
    virtual const char *sound() const = 0;
    virtual ~Animal() {}
};
class Dog : public Animal { public: const char *sound() const override { return "woof"; } };
class Cat : public Animal { public: const char *sound() const override { return "meow"; } };
int main() {
    Dog d; Cat c;
    const Animal *z[] = {&d, &c};
    for (auto a : z) cout << a->sound() << " ";
    cout << endl;
    return 0;
}