I have the following error.

[MazeStuck]

#include <iostream>
#include <cstddef>

void doAnything(std::nullptr_t ptr)//[Error] variable or field 'doAnything' declared void //[Error] 'nullptr_t' is not a member of 'std'
{
std::cout << "in doAnything()\n";
}

int main()
{
doAnything(nullptr); //[Error] 'nullptr_t' is not a member of 'std' // [Error] 'doAnything' was not declared in this scope

return 0;
}

[deleted account xyzzy]

PLEASE, do not double post.

http://www.cplusplus.com/forum/general/263639/

And learn to use code tags, it makes reading and commenting on your source code MUCH easier.

http://www.cplusplus.com/articles/jEywvCM9/

Hint: you can edit your post and add them.