Создание кнопки в Win32 Project

#include <windows.h>
#include <stdlib.h>
#include <string.h>
#include <tchar.h>
 
static TCHAR szWindowClass[] = _T("win32app");
static TCHAR szTitle[] = _T("Bike Shop");
 
HINSTANCE hInst;
 
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
 
int WINAPI WinMain(HINSTANCE hInstance,
                   HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine,
                   int nCmdShow)
{
    static HWND hButton, hListBox, hComboBox;
    PAINTSTRUCT ps;
    HDC hdc;
    
    WNDCLASSEX wcex;
    wcex.cbSize = sizeof(WNDCLASSEX);
    wcex.style          = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc    = WndProc;
    wcex.cbClsExtra     = 0;
    wcex.cbWndExtra     = 0;
    wcex.hInstance      = hInstance;
    wcex.hIcon          = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_APPLICATION));
    wcex.hCursor        = LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground  = (HBRUSH)(COLOR_WINDOW+1);
    wcex.lpszMenuName   = NULL;
    wcex.lpszClassName  = szWindowClass;
    wcex.hIconSm        = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_APPLICATION));
 
    if (!RegisterClassEx(&wcex))
    {
        MessageBox(NULL,
            _T("Call to RegisterClassEx failed!"),
            _T("Bike Shop"),
            NULL);
        return 1;
    }
 
    hInst = hInstance; 
    HWND hWnd = CreateWindow(
        szWindowClass,
        szTitle,
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT,
        1000, 800,
        NULL,
        NULL,
        hInstance,
        NULL
    );
 
     hButton = CreateWindow ((LPWSTR)"button", (LPWSTR)"Add", WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,  50, 55, 200, 30, hWnd, (HMENU)101, hInst, 0);
    
    if (!hWnd)
    {
        MessageBox(NULL,
            _T("Call to CreateWindow failed!"),
            _T("Bike SHop"),
            NULL);
 
        return 1;
    }
 
    ShowWindow(hWnd,nCmdShow);
    UpdateWindow(hWnd);
 
    MSG msg;
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
 
    return (int) msg.wParam;
}
 
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static HWND hButton;
    PAINTSTRUCT ps;
    HDC hdc;
 
    switch (message)
    {
    case WM_CREATE:
        {
        hButton = CreateWindow ((LPWSTR)"button", (LPWSTR)"Add", WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,  10, 5, 200, 30, hWnd, (HMENU)100, hInst, 0);
        }
        break;
    case WM_COMMAND:
        {switch (LOWORD(wParam))
        {
        case 100:
            {
                MessageBox (hWnd, (LPCWSTR)"Button", (LPCWSTR)"", 0);
            }
        }
        break;
    }
    case WM_PAINT:
        hdc = BeginPaint(hWnd, &ps);
        EndPaint(hWnd, &ps);
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
        break;
    }
    return 0;
}