C++ - Mutable Will Never be Constant
Mutuable is a keyword used in a class for a member variable and that variable will never be constant and can changed even with in a const function.
mutable int m;
void func1() const
// a = 10; Error: l-value specifies const object
// b = 20; Error: l-value specifies const object
m = 30;
int getA() const