Connect my ipad to pc with an HDMI cable

It is impossible. iPad HDMI adapters are used to connect the iDevice to a television or anything of the same kind. Same idea applies to that of a PC, as far as I am concerned. I never tried connecting an iPad to a PC with the purposeof viewing it there.

HDMI is a video-out system. It's used for connecting an iPad to a monitor or TV or something of the sort. If you have HDMI 'in' sockets on your computer then you could look at the image from there, but that's very rare: most HDMI sockets on a computer would be HDMI out sockets.

To view the output of your iPad on your PC, you would be best off trying something like Reflector or Airserver. Both of those let you set your computer up as an Airplay receiver, and you would then use Airplay mirroring on your iOS device.

The HDMI cable is for viewing on a TV. What type of computer has an HDMI input connector?

 Cheers, Tom 😉

My understanding is that AirPlay mirroring can output to an AppleTV only. It won't show an iDevice screen on a computer.

Reflector and Airserver will both take on the role of an AppleTV, acting as an Airplay receiver. I've used them to view and record the output of my iPad on my iMac using Airplay mirroring.