When should you use a class vs a struct in C++?

Question

In what scenarios is it better to use a struct vs a class in C++?

Answer 1

As every one says, the only real difference is the default access. But I particularly use struct when I don't want any sort of encapsulation with a simple data class, even if I implement some helper methods. For instance, when I need something like this:

struct myvec {
    int x;
    int y;
    int z;

    int length() {return x+y+z;}
};