#include <windows.h>

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);


int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, 
                    PWSTR pCmdLine, int CmdShow) {
                    
    MSG  msg;    
    WNDCLASSW wc = {0};
    wc.lpszClassName = L"Escape";
    wc.hInstance     = hInstance;
    wc.hbrBackground = GetSysColorBrush(COLOR_3DFACE);
    wc.lpfnWndProc   = WndProc;
    wc.hCursor       = LoadCursor(0, IDC_ARROW);
    
    RegisterClassW(&wc);
    CreateWindowW(wc.lpszClassName, L"Escape",
                  WS_OVERLAPPEDWINDOW | WS_VISIBLE,
                  100, 100, 250, 180, 0, 0, hInstance, 0);  

  while (GetMessage(&msg, NULL, 0, 0)) {
  
      TranslateMessage(&msg);
      DispatchMessage(&msg);
  }

  return (int) msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, 
    WPARAM wParam, LPARAM lParam) {
    
    switch(msg) {
  
        case WM_KEYDOWN:

            if (wParam == VK_ESCAPE) {
      
                int ret = MessageBoxW(hwnd, L"Are you sure to quit?", 
                                  L"Message", MB_OKCANCEL);
                                  
                if (ret == IDOK) {
          
                    SendMessage(hwnd, WM_CLOSE, 0, 0);
                }
             }
      
             break;

        case WM_DESTROY:

            PostQuitMessage(0);
            break; 
    }

    return DefWindowProcW(hwnd, msg, wParam, lParam);
}