rvm install new ruby version

C++
$ ruby -v 						# Check ruby version 
$ rvm install ruby-X.X.X        # Install specific ruby version
$ rvm list						# List ruby versions
$ rvm use ruby-X.X.X			# Choose a version to use
$ rvm use ruby-X.X.X --default  # Set a version as default\curl -sSL https://get.rvm.io | bash
Source

Also in C++: