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

See this for the full behaviors of C++ WRT constructors: http://en.wikipedia.org/wiki/Default_constructor

The simple answer is that if you specify a constructor, the compiler will not create a default one for you.

This rule applies to Java as well.