Unable to print the value of nullptr on screen

Question

I was reading about nullptr and doing workout on g++ and also on VS2010.

When I did

#include 
using namespace std;

aut         


        

Answer 1

This is because nullptr is of type std::nullptr_t, which does not define the appropriate operators for std::cout to be able print objects of that type. You can define the operator yourself like this:

//std::cout is of type std::ostream, and nullptr is of type std::nullptr_t
std::ostream& operator << (std::ostream& os, std::nullptr_t ptr)
{
    return os << "nullptr"; //whatever you want nullptr to show up as in the console
}

After this function is defined, it will be used to handle all attempts to print nullptr via an ostream. This way you don't need to cast nullptr every time you print it.