What is the output of code given below : #include<iostream.h> using namespace std; class Base { public: Base(){ cout<<"Base Const"; } virtual ~Base() { cout<<"Base dest"; } }; class Derived : public Base { public: Derived() { cout<<"Derived Const"; } ~Derived() { cout<<"Derived dest"; } }; int main() { Base *b=new Derived(); delete b; return 0; }
Base Const Derived Const Derived dest Base dest
When an object of a derived class is created, the base-class constructor runs first and then the derived-class constructor. Destruction happens in the reverse order. If the object is deleted through a base-class pointer, the derived destructor is reached only when the base destructor is declared virtual.
Step 1 — new Derived() first calls Base(), printing Base Const, and then Derived(), printing Derived Const.
Step 2 — delete b is applied to a Base *. Because ~Base() is virtual, the call is dispatched dynamically to ~Derived(), which prints Derived dest.
Step 3 — After the derived destructor finishes, the base destructor runs automatically and prints Base dest.
Printing Base dest before Derived dest would reverse the guaranteed destruction order. Printing Derived Const before Base Const reverses the construction order. Stopping after Base dest would happen only if the base destructor were not virtual, so that the derived part were never destroyed.
Base Const Derived Const Derived dest Base dest option is correct.
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