as shown in screenshot,cs50 library which include get_int(),get_float(),etc and update50 aren't working. I also followed the instructions given in the link https://cs50.ly/disk but nothing works..please help me out?
You're running an extremely old version of the IDE. Current version is v130. You probably won't be able to update your appliance.
The instructions on https://manual.cs50.net/ide/faqs#what-if-my-workspace-runs-out-of-disk-space or further down https://manual.cs50.net/ide/faqs#my-workspace-doesnt-look-like-davids-from-lecture-and-none-of-the-50-commands-work-what-should-i-do might be relevant.
Basically: Download your data, delete your appliance, create a new one by logging into cs50.io, upload your backed up data.