Arrrrgh C++ help

Are you sure its not in a namespace?
Or inside an IFDEF that is not defined?
EDIT
I just checked, and _WIN32_WINNT is not defined on my machine, and for INPUT, it needs to be > 0x0400.
You could define it manually before the include like this:
#define _WIN32_WINNT 0x0500
This way it would work, but it really shouldn't be done this way. I don't know why this constant is not defined.
EDIT2
Wait a minute, you do define _WIN32_WINNT as 0x0501 :S
Don't know why it doesn't work then :/
This works perfectly fine on my machine:

#define _WIN32_WINNT 0x0501
#include <windows.h>
//#include <stdout.h>
#include <stdio.h>
#include <iostream>
//#include "stdafx.h"

using namespace std;

int main()
{
	INPUT* x;
	//x=new struct tagINPUT;
	//printf(sizeof(struct tagINPUT));
	printf("hello");
	return 0;
}