how to go to a previous commit state

C++
git revert <commit hash># This will destroy any local modifications.
# Don't do it if you have uncommitted work you want to keep.
git reset --hard 0d1d7fc32

# Alternatively, if there's work to keep:
git stash
git reset --hard 0d1d7fc32
git stash pop
# This saves the modifications, then reapplies that patch after resetting.
# You could get merge conflicts, if you've modified things which were
# changed since the commit you reset to.# This will detach your HEAD, that is, leave you with no branch checked out:
git checkout 0d1d7fc32
Source

Also in C++: