Void CMainFrame::OnAdd()
{
CMenu *pMenu=GetMenu();
①HMENU hmenu; 
Hmenu=CreatePopupMenu();
②pMenu->InsertMenu(2, MF_BYPOSITION|MF_POPUP,(UINT)hmenu,”子菜单” ); 
CMenu *psub1=new CMenu;
CMenu *psub=pMenu->GetSubMenu(2); 
psub->InsertMenu(0,MF_BYPOSITION,ID_ITEM1,”ITEM1”);
psub->InsertMenu(1,MF_BYPOSITION|MF_SEPARATOR);
psub->InsertMenu(2,MF_BYPOSITION,ID_ITEM1,”ITEM2”);
CWnd::DrawMenuBar();
}这是程序的功能是为ID_ADD映射处理函数,首先得到主菜单的指针,请问接下的①语句是什么含义?