註冊表控制軟體使用次數

HKEY key;
CString sKeyPath;
sKeyPath="Software//SoftTryTimeTest";

if(RegOpenKey(HKEY_CURRENT_USER,sKeyPath,&key)!=0
&& RegOpenKey(HKEY_CURRENT_USER,sKeyPath,&key)!=ERROR_SUCCESS
) //首次使用
{
    //在註冊表中記錄已使用的次數
    ::RegCreateKey (HKEY_CURRENT_USER,sKeyPath,&key);
    ::RegSetValueEx (key,"Try time",0,REG_SZ,(unsigned char *)"5",2);
    ::RegCloseKey (key);
    MessageBox("你只能使用5次","系統提示",MB_OK|MB_ICONEXCLAMATION);
}
else //已經存在註冊表資訊
{
    CString sTryTime;
    int nTryTime;
    LPBYTE Data=new BYTE[80];
    DWORD TYPE=REG_SZ;
    DWORD cbData=80;

    //取出已經使用次數
    ::RegQueryValueEx (key,"Try time",0,&TYPE,Data,&cbData);
    sTryTime.Format ("%s",Data);
    nTryTime=atoi(sTryTime);
    if(nTryTime <1)
    {
    MessageBox("最大試用次數已過","系統提示",MB_OK|MB_ICONSTOP);

    return false;
    }
    nTryTime--;
    sTryTime.Format ("%d",nTryTime);
    ::RegSetValueEx (key,"Try time"
    ,0,REG_SZ
    ,(unsigned char *)sTryTime.GetBuffer (sTryTime.GetLength ())
    ,2);
    ::RegCloseKey (key);
    MessageBox("你還可以試用"+sTryTime+"次!","系統提示",MB_OK|MB_ICONEXCLAMATION);
}