I have tried every way I could find--terminal commands, the uninstall in the package contents, and the uninstall in the "top left corner" of the open app, as well as the uninstall within the app. I really need to delete this program.
A few ideas here (sorry but I don't have a Mac myself)
https://community.ccleaner.com/topic/62690-how-to-remove-ccleaner-from-macos/
use their unistaller first. then
download findanyfile.app
search for all files on your startup drive that contain com.piriform.ccleaner (make sure invisible items are shown)
select those and right click/contextual menu, move to trash OR delete immediately. all done. NEVER will install this app again, ever. it runs all the time in the background and auto starts without anyway to disable it. I want to use it when I choose to; also a privacy invader. bad app.