C++: What is the difference between struct and class in C++?

Only difference is default access modifier.

1struct S {
2    int x;  // public by default
3};
4
5class C {
6    int x;  // private by default
7public:
8    int getX() { return x; }
9};

Inheritance:

• struct — public by default.
• class — private by default.

Convention:

• struct — passive data structure.
• class — object with encapsulation.