Why people say that c/c++ instead of c or c++?

Question

I am confused.

Answer 1

There's no difference.
The symbol / can also be used as the word or.
There's nothing to be confused about.

Answer 2

C++ has developed from C. C is for a big part a subset of C++.

So probably this makes people sum up the two languages into a close team with /.

Answer 3

Let's see people talking about mobile apps development, which language is good. They say Java, python, c/c++. That is my confusion. Why do not say Java, python, c, c++. Why use this / when c and c++ is different languages.