Is there any way to use c++ without xcode installing

Sign-up for a free developer account at developer.apple.com. You can use the same AppleID and password as for the support communities sign-in. You do not need Xcode at all, and can save yourself the 5GB download. Apple makes Command Line Tools that is a 174MB download that gives you a full C/C++/Objective-C compilation environment.

At the bottom of the Apple developer landing page is a link to Downloads, and at the bottom of that page is this download link for more downloads. The command line packages are named: Command Line Tools (os version) for Xcode n.n. So for High Sierra, you want Command Line Tools (macOS 10.13) for Xcode 9.2. As of this post, the version for Xcode 9.3 is really a beta when you look at the filename of the download. Stay away from the beta stuff, and if you install the 9.2 version of command line tools, the Mac App Store will show you an update for 9.3 when it is out of beta.

If your version of OS X/macOS is older, then find the last Command Line Tools shown for that operating system. It should be worth noting that Apple's compilation environment is not based on GNU compiler technology, and uses the Clang/LLVM technology.