Why does abstract base class need explicit default constructor?

For below code,

#include <iostream>

class virtualBase {
public:
  virtual void printName() = 0;

//   virtualBase() = default;

private:
  virtualBase(const virtualBase &) = delete; // Disable Copy Constructor
  virtualBase &
  operator=(const virtualBase &) = delete; // Disable Assignment Operator
};

class derivedClass : public virtualBase {
public:
  void printName() { std::cout << "Derived name" << std::endl; };
  derivedClass() {};
  ~derivedClass() = default;
};

int main() {
  derivedClass d;
  d.printName();
  return 0;
}

I need to uncomment the default constructor definition in base class for the compilation to succeed.

I am seeing the following compilation error:

test.cpp: In constructor ‘derivedClass::derivedClass()’:
test.cpp:18:18: error: no matching function for call to ‘virtualBase::virtualBase()’
   18 |   derivedClass() {};
      |                  ^
test.cpp:10:3: note: candidate: ‘virtualBase::virtualBase(const virtualBase&)’ <deleted>
   10 |   virtualBase(const virtualBase &) = delete; // Disable Copy Constructor
      |   ^~~~~~~~~~~
test.cpp:10:3: note:   candidate expects 1 argument, 0 provided

My understanding is that compiler provides it own default constructor esp in case like this where the class is really simple.

What am I missing here?

Thanks

>Solution :

Declaring any constructor explicitly prevents declaration of the implicit default constructor.

You do declare the copy constructor explicitly (even if you then define it as deleted).