What obvious thing am I overlooking in this failing C++ class instantiation? - c++

Question

I'm writing code for an Arduino-based retirement countdown clock (a gift for a coworker), and have grouped some code into a simple class. This chunk of code gives me the error "error: 'rd' does not name a type" when I compile it in the current (1.6.7) Arduino IDE:
#include "RetirementDisplay.h"
RetirementDisplay* rd;
rd = new RetirementDisplay(&update_lcd);
Oddly, this code compiles without error:
#include "RetirementDisplay.h"
RetirementDisplay* rd = new RetirementDisplay(&update_lcd);
But then when I try to use a member function (like rd->add_screen()) of the newly created rd object, I get the same "rd does not define a type" error, which is completely illogical to me. My C++ is super rusty, though, so I assume there's probably something I'm overlooking here.
The update_lcd method is defined earlier in the same file, and does take two String arguments, so I don't think it's upset about that.
The contents of RetirementDisplay.h are similarly simple; it's just a linked list and a couple of convenience functions to bundle related functionality together while tracking what "screen" (just a couple of printf formats) should currently be active. Don't judge me on my sketchy naming convention; this was supposed to be a quick project. ;)
#ifndef RetirementDisplay_h
#define RetirementDisplay_h
#include "RetirementScreen.h"
class RetirementDisplay {
protected:
RetirementScreen* head;
RetirementScreen* current;
void (*updater)(String, String);
public:
RetirementDisplay( void(*)(String,String) );
void add_screen(RetirementScreen*);
void update();
void next();
void prev();
};
#endif

Answer 1

It looks like this line is intended to be an assignment statement:
rd = new RetirementDisplay(&update_lcd);
but statements must be inside functions, like this:
#include "RetirementDisplay.h"
void myfunction()
{
RetirementDisplay* rd;
rd = new RetirementDisplay(&update_lcd);
}
However, variable declarations can be outside functions, so that is why you don't get an error on this line:
RetirementDisplay* rd = new RetirementDisplay(&update_lcd);