Calling a constructor of the base class from a subclass' constructor body

Question

I was under impression that it\'s impossible, see for example: Calling the constructor of the base class after some other instructions in C++
But the following program

Answer 1

The call inside the child class constructor is not calling the base class constructor, it is creating a temporary, unnamed and new object of type Person. It will be destroyed as the constructor exits. To clarify, your example is the same as doing this:

Child() { c = 1; Person tempPerson; }

Except in this case, the temporary object has a name.

You can see what I mean if you modify your example a little:

class Person
{
public:
    Person(int id):id(id) { std::cout << "Constructor Person " << id << std::endl; }
    ~Person(){ std::cout << "Destroying Person " << id << std::endl; }
    int id;
};

class Child : public Person
{
public:
    Child():Person(1) { c = 1; Person(2); }
int c;
};

int main() {
Child child;

Person(3);
return 0;
}

This produces the output:

Constructor Person 1
Constructor Person 2
Destroying Person 2
Constructor Person 3
Destroying Person 3
Destroying Person 1