When do we need to have a default constructor?

Question

My question is simple. When do we need to have a default constructor? Please refer to the code below:

class Shape
{
    int k;

public:
    Shape(int n) : k         


        

Answer 1

Compiler generates default constructor in case when you have not define any constructor. But if you have defined any constructor that takes some argument or not. The compiler will use that constructor and will not generate default constructor with zero argument.