not so obvious pointers

Question

I have a class :

class X{
 public :
 void f ( int ) ;
 int a ;
} ;

And the task is "Inside the code provide declarations for :

• pointer to int variable of class X
• pointer to function void(int) defined inside class X
• pointer to double variable of class X"

Ok so pointer to int a will be just int *x = &a, right ? If there is no double in X can I already create pointer to double inside this class ? And the biggest problem is the second task. How one declares pointer to function ?

Answer 1

You need to declare them as pointer-to-members. Pointers to members are different than usual pointers in that they are the address of a member of a structure or class, not an absolute address like regular pointers.

For more information, read this.

Answer 2

A pointer to any type is declared with an '*' after the type name and the variable name:

Franks_Class * p_franks_class; // Declares a pointer to an instance of Franks_Class.

The more obscure declaration is for the function:

typedef void (*My_Int_Function_Ptr)(int parameter);

which declares a type (synonym), named My_Int_Function_Ptr, a pointer to a function taking an int parameter and returning void.

From this and a good C++ book, you should be able to answer the rest of your questions.