windows.h에는 어떤 기능이 있나요?

#include "stdafx.h"
#include<windows.h>
int main() {
    HWND window;    //定义一个窗口句柄变量，用来储存窗口句柄
    /*FindWindow("这里填窗口类名","这里填窗口标题名")
    窗口类名和窗口标题名可以只填一个，不填的用NULL填充*/
    window = FindWindow(NULL,"文本.txt - 记事本");  //查找标题为"文本.txt - 记事本"的窗口
    SendMessage(window,WM_CLOSE,0,0);              //向窗口发送关闭指令
    return 0;
}

#include "stdafx.h"
#include<windows.h>
int main() {
    POINT mouse;
    HWND window;
    while (1) {
        GetCursorPos(&mouse);
        window = WindowFromPoint(mouse);
        /*SendMessage(窗口句柄,消息类型,消息附带内容,消息附带内容)
        比如我这里选定的消息类型是WM_CHAR
        消息附带内容为WPARAM(&#39;a&#39;)
        所以消息附带内容就是模拟键盘向窗口输入a*/
        SendMessage(window,WM_CHAR,WPARAM(&#39;a&#39;),0);
        Sleep(100);
    }
    return 0;
}

#include "stdafx.h"
#include<windows.h>
int main() {
    POINT mouse;        //定义一个结构体变量储存鼠标位置
    HWND window;
    while (1) {
        GetCursorPos(&mouse);   //获取到当前鼠标位置
        /*WindowFromPoint(鼠标位置变量名)*/
        window = WindowFromPoint(mouse);
        SendMessage(window,WM_CLOSE,0,0);
        Sleep(100);
    }
    return 0;
}