class ErEngine{
Properties Er_Properties;
public:
LRESULT	Er_CreateWindow(HINSTANCE hInst, int nCmdShow);
LRESULT CALLBACK Er_WindowProc(HWND hWnd,UINT message,WPARAM wParam,LPARAM lParam);
};

#include <windows.h>
#include <windowsx.h>
#include "ErEngine.h"

LRESULT CALLBACK ErEngine::Er_WindowProc(HWND hWnd,UINT message,WPARAM wParam,LPARAM lParam)
{

};

LRESULT ErEngine::Er_CreateWindow(HINSTANCE hInstance, int nCmdShow)
{
   HWND hWnd;
    WNDCLASSEX wc;
    ZeroMemory(&wc, sizeof(WNDCLASSEX));
    wc.cbSize = sizeof(WNDCLASSEX);
    wc.style = CS_HREDRAW | CS_VREDRAW;
//////////////////////////////////////////////////////////////////////////////////////

    wc.lpfnWndProc = ErEngine::Er_WindowProc;
//here is my problem :(
//////////////////////////////////////////////////////////////////////////////////////
    wc.hInstance = hInstance;
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)COLOR_WINDOW;
    wc.lpszClassName = "WindowClass1";
    RegisterClassEx(&wc);
    hWnd = CreateWindowEx(NULL,
                          "WindowClass1",   
                          "Our First Windowed Program",   
                          WS_OVERLAPPEDWINDOW,    
                          300,   
                          300,   
                          500,  
                          400,   
                          NULL,  
                          NULL,    
                          hInstance,    
                          NULL);    
    ShowWindow(hWnd, nCmdShow);
};