Pointer to Members implemented in C++

 We know that to access a structure member we use a '.' or '->' operator. Also, to dereference a pointer we use the '*' operator. To access the structure element through this pointer we need '.' or '->' to reach the element and '*' to deference the pointer. To carry out the access & deferenceing simultaneously, C++ provides two new operators: '*' and '->'.  These are known as pointer to member operators.



#include<iostream.h>
struct sample
{
    int a;
    float b;
    int *c;
    float *d;
    int **e;
    float **f;
};
void main()
{
    int sample::*p1=&sample::a;
    float sample::*p2=&sample::b;

    int *sample::*p3=&sample::c;
    float *sample::*p4=&sample::d;

    int **sample::*p5=&sample::e;
    float**sample::*p6=&sample::f;

    sample so={10,3.14,&so.a,&so.b,&so.c,&so.d};
    sample *sp;

    sp=&so;

    //pointer to member operators using *

    cout<<endl<<so.*p1<<endl<<so.*p2;
    cout<<endl<<*(so.*p3)<<endl<<*(so.*p4);
    cout<<endl<<**(so.*p5)<<endl<<**(so.*p6);

   // pointer to member operators using ->

    cout<<endl<<sp->*p1<<endl<<sp->*p2;
    cout<<endl<<*(sp->*p3)<<endl<<*(sp->*p4);
    cout<<endl<<**(sp->*p5)<<endl<<**(sp->*p6);


    //store new values

    *(so.*p3)=20;
    **(sp->*p6)=6.28;

    //output change values through p1 & p2
   cout<<endl<<so.*p1<<endl<<so.*p2;

}