Class Templates..

Question

Why in the slide 2/5 of class templates lesson, the first class is "private" and the second "public"?

Answer 1

What you see in that slide is a template class example.

- template <class T> here is used to introduce a template, we use template so we can create a Pair instance containing a couple (2 items) of a similar class, by using template we can have a Pair of int, float, double, object or other things without having to create a Pair class specific for each type.

template <class T>
class Pair {

- private: defines whatever follows are all private members. "first" and "second" member are private, they can't be accessed directly, a getter/setter method is needed to manipulate private members.

private:
T first, second;

- public: defines whatever follows are all public members. Public members are accessible directly without a need of getter/setter. A constructor declaration is written here, where private members "first" and "second" are assigned a value, using constructor initializer, "first" is assigned "a", and "second" is assigned "b".

public:
Pair (T a, T b):
first(a), second(b) {
}
};

Answer 2

Baldemar Aguirre are you taking about this one ?

https://www.sololearn.com/learn/CPlusPlus/1916/

I mean variable first and second as private ?