Question

Given the code below, why would I get an error about A’s destructor being private? Obviously it is private, but I don’t understand why initializing B’s A object instance in this way would cause the destructor of A to be called.

Apologies for any typos, I’m recreating the code from memory from a non-networked system and don’t have a compiler.

class A
{
    public:
        A(int val) : x(val) {}

    private:
        int x;
        ~A() {}
};

class B
{
    public:
        B() : aInstance() {}

    private:
        A aInstance;
};

int main()
{
    B b;
}

Answer 1

Initializing itself doesn’t involve using the dtor, but the instance of B is destroyed at the end of main. The B contains an A, so when the B is destroyed,the A must be destroyed as well — but A‘s dtor isn’t available, so the code to do that can’t be generated.