With C, you need to carefully craft your own gun with just iron ingots and a hammer. You will shoot yourself in the foot, but at least you'll have the knowledge that it was your craftsmanship that led to it.

With C++, there are already prebuilt guns and tons of modifications that you can combine at will. If you shove it in the right way, you can make a flintlock shoot a 50 cal, but don't complain when your whole leg gets obliterated.