Virtual functions vs. Templates (C++)

Virtual functions

They get resolved at run-time, leading to a shorter compile-time and less binary code.

#include <iostream>

class Animal
{
public:
    virtual void makeSound() = 0;
};

class Cow : public Animal
{
public:
    void makeSound() { std::cout << "Moo" << std::endl; };
};

int main()
{
    Cow cow;
    cow.makeSound();

    return 0;
}

---

Templates

They get resolved at compile-time, leading to a shorter run-time and more binary code.

#include <iostream>

template <typename T>
class Animal
{
public:
    void makeSound() { t.makeSound(); };

private:
    T t;
};

class Cow
{
public:
    void makeSound() { std::cout << "Moo" << std::endl; };
};

int main()
{
    Animal<Cow> cow;
    cow.makeSound();

    return 0;
}