class Bar;
public foo(Bar*);

class FooBar{
     void (*fp)(Bar*);
     <snip/>
         fp = foo;
     public:
         (*fp)(Bar*) get_fp(){
             return fp;
         }
}

class Foo{
     void (*fp)(Bar*);
     <snip/>
         fp = foobar->get_fp();
}

#include<iostream>
using namespace std;

class Bar                   // a sample class Bar
{
    public:             
        int i;              // assume a simple variable for testing.
        Bar()
        {
            i = 10;         // initialize i to 10 in constructor
        }
};


void foo(Bar* x)        // function that takes Bar* as argument.
{
    cout<<"The value of i is "<<x->i<<endl;         // print the value of i in the Bar Object
}

//IMPORTANT PART

typedef void (*fp)(Bar*);   // using typedef simplifies coding

// It also aids in easy return of function pointer


class FooBar
{          
    fp ptr;                 // create new function pointer to foo
   
public: 
    FooBar()                // initialize function pointer to foo in constructor
    {
        ptr = &foo;
    }
    fp get_fp()             // a function that returns a function pointer to foo.
    {
        cout<<"Returned a function pointer..."<<endl;
        return ptr;
    }
    void put_fp(fp x)       // a function that has function as the argument.
    {
        ptr = x;
        cout<<"Changed the Function pointer..."<<endl;
    }
};


int main()
{
    FooBar *foobar = new FooBar();  // create new Object

    fp ptr;                         // a function pointer to foo

    ptr = foobar->get_fp();         // THERE!!!! We use the function to initialize function pointer

    Bar x;                          // create a new Bar object to verify
    (*ptr)(&x);                     // See the output!!!!!

    foobar->put_fp(ptr);            // passing function pointer to a function

    return 0;
}