自动更改桌面背景 c/c++ win32

这个程序仅供编程参考
若想在平时用，请下载微软的wallpaper changer
我这个程序实现了定时更换桌面背景的功能
命令行 wallpaper "your images' directory path" time_in_minute
编程要点
findfirstfile findnextfile 查找图像文件
SystemParametersInfo  修改系统信息，在这儿当然是桌面背景
注册表操作 保存信息
如果做得实用，应加入开机启动功能，自然还要gui
//wallpaper.c
//by onezeros@yahoo.cn||Zhijie Lee
//usage:wallpaper "full directory path" interval
// interval is in minutes
#include <windows.h>
#include <iostream>
#include <string>
using namespace std;
int main(int argc, char* argv[])
{
/* argc=3;
argv[1]="E:\\picture\\testbmp";
argv[2]="1";
*/ LPCSTR currentDir;
LPCSTR currentImage;
int interval;

HKEY hKey;
WIN32_FIND_DATAA FileData;
HANDLE hFind;

//initialize parameters
if(argc==1){
//find parameters in registry
if(RegOpenKeyA(HKEY_LOCAL_MACHINE,(LPCSTR)"Software\\wallpaper",
&hKey)!=ERROR_SUCCESS||
RegQueryValueExA(hKey,(LPCSTR)"interval",0,NULL,
(LPBYTE)interval,NULL)!=ERROR_SUCCESS||
RegQueryValueExA(hKey,(LPCSTR)"directory",0,NULL,
(LPBYTE)currentDir,NULL)!=ERROR_SUCCESS||
RegQueryValueExA(hKey,(LPCSTR)"image",0,NULL,
(LPBYTE)currentImage,NULL)!=ERROR_SUCCESS){
//if connot be found ,wrong usage
cout<<"wrong usage"<<endl
<<"Please use it like this"<<endl
<<"wallpaper \"D:\\Files\\Images\" 30"<<endl
<<"30 is the interval in minutes or"<<endl
<<"wallpaper \"D:\\Files\\Images\""<<endl
<<"with 30 minutes as default interval"<<endl;
exit(1);
}else{
hFind=FindFirstFileA(currentImage,&FileData);
if(hFind==INVALID_HANDLE_VALUE){
cout<<"connot open file";
exit(1);
}
}
}else if(argc==3){
interval=60000*atoi(argv[2]);
currentDir=(LPCSTR)argv[1];
SetCurrentDirectoryA(currentDir);
hFind = FindFirstFileA((LPCSTR)"*.jpg",&am