Practical application of class destructor

Question

I\'m currently trying to learn about classes and constructors/destructors. I understand what the two do, but I\'m having a harder time with the destructors because I can\'t

Answer 1

Extending @Als's answer here, for example you have a class,

class A {
    B* ptrB; // B is another class / struct / internal type
    A() { ptrB = new B(); }
}

int main() {
    A* ptrA = new A();
    // Do something with A
    delete ptrA; // This does not free ptrA->ptrB
}

To take care of this problem, declare a destructor in A as follows,

~A() { delete ptrB; } // This is called every time delete is called on
                      // an object of A