建立一個完整的視窗需要經過下面四個操作步驟：

1. 設計一個視窗類；
2. 註冊視窗類；
3. 建立視窗；
4. 顯示及更新視窗。

#include <Windows.h>
#include <stdio.h>
LRESULT CALLBACK WinSunProc
(
    HWND hwnd,
    UINT uMsg,
    WPARAM wParam,
    LPARAM lParam
);
int WINAPI WinMain
(
    HINSTANCE hInstance,        //handle to current instance
    HINSTANCE hPrevInstance,    //handle to previous instance
 

    LPSTR lpCmdline,            //command line
    int nCmdShow                //show state
)
{
    //design window class
    WNDCLASS wndcls;
    wndcls.cbClsExtra = 0;
    wndcls.cbWndExtra = 0;
    wndcls.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
    wndcls.hCursor = LoadCursor(nullptr, IDC_CROSS);
    wndcls.hIcon = LoadIcon(nullptr
 
, IDI_ERROR);
    wndcls.hInstance = hInstance;
    wndcls.lpfnWndProc = WinSunProc;
    wndcls.lpszClassName = "SCU2016";
    wndcls.lpszMenuName = nullptr;
    wndcls.style = CS_HREDRAW | CS_VREDRAW;
    //register window class
    RegisterClass(&wndcls);
    //creat window
    HWND hwnd;               //handle
 

    hwnd = CreateWindow("SCU2016", "ZHAOMIN", WS_OVERLAPPEDWINDOW,
        0, 0, 600, 400, nullptr, nullptr, hInstance, nullptr);
    //(className,windowName,windowStyle
    //show window
    ShowWindow(hwnd, SW_SHOWNORMAL);
    //update window
    UpdateWindow(hwnd);
    MSG msg;
    while (GetMessage(&msg, nullptr, 0, 0))//(message,handle,mix,max)
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return 0;
}
//callback function-視窗過程函式
LRESULT CALLBACK WinSunProc
(
    HWND hwnd,
    UINT uMsg,
    WPARAM wParam,
    LPARAM lParam
)
{
    switch (uMsg)
    {
    case WM_CHAR:
        char szChar[20];
        sprintf_s(szChar, "char is %d", wParam);
        MessageBox(hwnd, szChar, "ZHAOMIN", 0);
        break;
    case WM_LBUTTONDOWN:
        MessageBox(hwnd, "mouse clicked", "ZHAOMIN", 0);
        HDC hdc;
        hdc = GetDC(hwnd);
        TextOut(hwnd, 0, 50, "compucture", strlen("compucture"));
        ReleaseDC(hwnd, hdc);
        break;
    case WM_PAINT:
        break;
    case WM_CLOSE:
        break;
    case WM_DESTROY:
        break;
    default:
        return DefWindowProc(hwnd, uMsg, wParam, lParam);
    }
    return 0;
}