Окно программы по центру экрана

#include <windows.h>
#include <stdlib.h>
#include <string.h>
#include <tchar.h>
 
static TCHAR szWindowClass[] = _T("win32app");
static TCHAR szTitle[] = _T("Win32 Guided Tour Application");
 
HINSTANCE hInst;
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
 
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    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("Win32 Guided Tour"), NULL);
        return 1;
    }
    hInst = hInstance;
 
    HWND hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 500, 100, NULL, NULL, hInstance, NULL);
 
    if(!hWnd)
    {
        MessageBox(NULL, _T("Call to CreateWindow failed!"), _T("Win32 Guided Tour"), 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)
{
    PAINTSTRUCT ps;
    HDC hdc;
 
    switch(message)
    {
        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;
}