C++ constructor definition differences in the code given below [closed]

Answer 1

For some odd reasons you are not allowed to repeat the default value for a parameter:

class Box
{
    int x;
public:
    Box(int a=0);
//------------^  given here
    void print();
};

Box::Box(int a=0)
//------------^^  must not be repeated (even if same value)
{
    x = a;
}