What is pointer to member?
- Not to a specific instance of that member in an object. This type of pointer is called a pointer to a class member or a pointer-to-member. It is not same as normal C++ pointer. Instead it provides only an offset into an object of the member’s class at which that member can be found. Since member pointers are not true pointers, the . and → can not be applied to them. Instead we must use the special operators .* and →* . They allow access to a member of a class.
-
Example :#include <iostream>
using namespace std;
class MyClass
{
public:
int val;
MyClass(int i)
{
val = i;
}
int double_val()
{
return val + val;
}
};
int main()
{
int MyClass::*data; //data member pointer
int(MyClass::*func)(); //function member pointer
MyClass obj1(1), obj2(2); //create objects
data =&MyClass::val; //get offset of data val
func=&MyClass::double_val; //get offset of function double_val()
cout << “The values are:”;
cout << ob1.*data << “ “ << ob2.*data << “\n”;
cout << “Here they are doubled:”;
cout << (ob1.*func)() << “ “ << (ob2.*func)() << “\n”;
return 0;
}
- Here data and func are member pointers. As shown in the program, when declaring pointers to members, you must specify the class and use the scope resolution operator.
