Error : base class constructor must explicitly initialize parent class constructor

Question

I am new to c++. When I try to compile the code below , I get this error

constructor for \'child\' must explicitly initialize the base class \'parent\' whic

Answer 1

The parent class has an explicit constructor, so compiler will not add an implicit 'empty' constructor to it. Additionally your constructor has a parameter, so compiler can not generate an implicit call to it. That's why you must do it explicitly.

This way:

 child::child(int a) : parent(a)
 {
 }