#include <windows.h>
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam){
   HDC hDC; 
   PAINTSTRUCT ps;
  ...
   return 0;
};

#include <windows.h>
void AddMenu(HWND hWnd){
   hMenu = CreateMenu();
   ...
   SetMenu(hWnd, hMenu);
};

#include <windows.h>
#include "WndProc.h"

extern HMENU hMenu;

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow){
   HWND hMainWnd;
   char szClassName[] = "MyClass";
   
   WNDCLASSEX wc;
   wc.cbSize = sizeof(wc);            
   wc.style = CS_HREDRAW | CS_VREDRAW;   
   wc.lpfnWndProc = WndProc;         
   wc.cbClsExtra = 0;               
   wc.cbWndExtra = 0;               
   wc.hInstance = hInstance;         
   wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
   wc.hCursor = LoadCursor(NULL, IDC_ARROW);   
   wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);   
   wc.lpszMenuName = NULL;            
   wc.lpszClassName = szClassName;      
   wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
   if(!RegisterClassEx(&wc)){ MessageBox(NULL, "Cannot register class", "Error", MB_OK); return 0; }
       
        //----------------------------
   hMainWnd = CreateWindow(
      szClassName, 
      "A Hello Application",
      WS_OVERLAPPEDWINDOW,   
      CW_USEDEFAULT,         
      0,                  
      600,               
      400,               
      (HWND)NULL,            
      hMenu,      
      (HINSTANCE)hInstance,   
      NULL               
   );
   if(!hMainWnd){ MessageBox(NULL, "cannot crate main window", "error", MB_OK); return 0; }
   //----------------------------
   ShowWindow(hMainWnd, nCmdShow);
   //UpdateWindow(hMainWnd);
   
   MSG msg;
   while (GetMessage(&msg, NULL, 0,0)){
      TranslateMessage(&msg);
      DispatchMessage(&msg);
   }
   
   return msg.wParam;
};

#ifndef TOPMENU_H
#define TOPMENU_H

void AddMenu(HWND hWnd);

#endif TOPMENU_H

#include <windows.h>

HMENU hMenu;
enum MENU {
   NEW, OPEN, SAVE, SAVEAS, EXIT,
   UNDO, REDO, COPY, PAST
};

void AddMenu(HWND hWnd){
   hMenu = CreateMenu();
   
      //FILE
      HMENU hFileMenu = CreateMenu();
         AppendMenu(hFileMenu, MF_STRING, MENU::NEW, "New \t ctrl+n");
         AppendMenu(hFileMenu, MF_STRING, MENU::OPEN, "Open \t ctrl+o");
         AppendMenu(hFileMenu, MF_STRING, MENU::SAVE, "Save \t ctrl+s");
         AppendMenu(hFileMenu, MF_STRING, MENU::SAVEAS, "Save As...");
         AppendMenu(hFileMenu, MF_SEPARATOR, NULL, NULL);//просто лини¤   
         AppendMenu(hFileMenu, MF_STRING, MENU::EXIT, "Exit \t alt+f4");
      AppendMenu(hMenu, MF_POPUP, (UINT_PTR)hFileMenu, "File");
      //EDIT
      HMENU hEditMenu = CreateMenu();
         AppendMenu(hEditMenu, MF_STRING, MENU::UNDO, "Undo");
         AppendMenu(hEditMenu, MF_STRING, 2, "Redo");
         AppendMenu(hEditMenu, MF_SEPARATOR, NULL, NULL);
         AppendMenu(hEditMenu, MF_STRING, 2, "Copy");
         AppendMenu(hEditMenu, MF_STRING, 2, "Past");
         AppendMenu(hEditMenu, MF_SEPARATOR, NULL, NULL);
            //submenu
            HMENU hEditSubMenu = CreateMenu();
            AppendMenu(hEditSubMenu, MF_STRING, 12, "SubMenu Item1");
            AppendMenu(hEditSubMenu, MF_STRING, 12, "SubMenu Item2");
            AppendMenu(hEditSubMenu, MF_STRING, 12, "SubMenu Item3");
         AppendMenu(hEditMenu, MF_POPUP, (UINT_PTR)hEditSubMenu, "Open SubMenu");
         
      AppendMenu(hMenu, MF_POPUP, (UINT_PTR)hEditMenu, "Edit");
         
      //INFO
      AppendMenu(hMenu, MF_STRING, NULL, "Info");
      
   SetMenu(hWnd, hMenu);
};

#ifndef WNDPROC_H
#define WNDPROC_H

LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

#endif WNDPROC_H

#include <windows.h>
#include "TopMenu.h"

LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam){
   HDC hDC; 
   PAINTSTRUCT ps;
   RECT rect;
   
   switch (uMsg)
   {
      case WM_CREATE:
         AddMenu(hWnd);
      break;
      
      case WM_PAINT:
         hDC = BeginPaint(hWnd, &ps);
         GetClientRect(hWnd, &rect);
         DrawText(hDC, "HELLO WORLD", -1, &rect, DT_SINGLELINE | DT_CENTER | DT_VCENTER);
         EndPaint(hWnd, &ps);
         break;
         
      case WM_CLOSE:
         DestroyWindow(hWnd);
         break;
      case WM_DESTROY:
         PostQuitMessage(0);
         break;
      default:
         return DefWindowProc(hWnd, uMsg, wParam, lParam);
   }
   
   return 0;
};

g++ main.cpp TopMenu.cpp WndProc.cpp -mwindows