Answer 1

They are a way of structuring code.

When you first start out you will put everything into the main function. As your programs become larger, you will start using functions, then classes.

Just keep practicing, you will get it eventually :)

Have you seen C++ vectors, or strings? Somebody somewhere wrote the `vector` and `string` class, and they are thousands of lines long, but you can easily use them by doing

string s = "Hello world";

Here's how `string` is defined: https://gcc.gnu.org/onlinedocs/gcc-4.6.2/libstdc++/api/a00771_source.html

It's a lot.