It contains the processing device.
Neither one. It is the processor.
inpuit
The "tower" part of a computer contains most of the computer. It is the cabinet that contains input and output devices, as well as storage devices. However, collectively speaking, the label of "processing device" would be more accurate. Or you can say it is an I/O and processing device with storage.
A computer is an output device.
Technically it's neither as it's just a shell that houses the devices. However, if you just mean the computer as a whole, then it is of course both because it's made up of input and output devices.
Define the output device in computer?
Output is like, if you print something, the information on the paper is output. If you are listening to music on the computer, the sound is output. If you are watching a movie, the actions, the images, and the sound is output. In other words, output is something the computer provides for you.
The result of a computer's processing is known as "output."
Input
The computer output is what one will see on a screen. For example the image text can be seen on ones computer would be considered output. There is also audio output which is what one hears through computer speakers.
output
A rather simplistic answer is: The keyboard is an input device, and is plugged into the computer tower, and thus is connected to the motherboard and processor, etc. The monitor is an output device and shows the graphical output from the motherboard for the user to see on the screen.
The output of a computer can be purely visual, in which case the output device is a monitor, or it can be printed, in which case the output device is a printer; when computers produce sound, the output device is a speaker.