Hi, I need good and briefly explaination of those questions here. Thank you in advance

Language c++

What is the difference between a class and a struct? What does it mean that a variable is private? What is function overloading? What does it mean if we write using namespace std? How are pointers and arrays related? If we have int x[10], and want to set int y = x[2]. Can we do this another way? What is a scope? How is scope related to dynamic memory allocation? How do you access member variables of an object via a pointer (eg x on GridPoint, via GridPoint *start_ptr)?