visual studio code is not autocompleting std:: in c++ on ubuntu

The behaviour i am looking for is when i type

using std::co then i expect it to autocomplete to cout (or at least suggest)

using std::vect then i expect it to autocomplete to vector

I have it set up on my laptop and it works perfectly fine ... it is just on my main vm that it does not. Sadly after a few hours of tinkering and googling not figured it out.

installed c++, build essentials, clang-format-3.8 vscode, c++ extention and c++ autocomplete. noticed the one that worked had this added to the c_cpp_properties (not that i expected clang to help but was out of other options.)

,
    "clang_format" : {
        "style" : "file",
        "fallback-style" : "LLVM",
        "sort-includes" : false
    }

I think it is probably a package difference but cannot see where that difference is. I also cannot find the difference in vscode config if there is one.