// this file illustrates pointers to integers, objects, and functions.

#include <iostream.h>

void f(int* x)
{ *x = 6; }

void g(int x)
{ x = 6; }


class cell
{ public:
    int car;
    cell* cdr;
    cell(int initial)
     { car = initial;
       cdr = 0;       //  0==NULL
     }
};

int f1(int x)
{ return x+2; }

int f2(int y)
{return y-2; }

int f3(int x, int (*fun)(int))
{ return (*fun) (x); }


void main()
{ int a;
  int* b;
/*
  a = 5;
  b = &a;

  cout << "\n the value of b is " << b;
  cout << "\n the value of *b is " << *b;

  cell c(3);

  cell* d;
  d = new cell(4);

  cout << "\n the value of c.car is " << c.car;
  cout << "\n the value of d->car is " << d->car;
  cout << "\n the value of (*d).car is " << (*d).car;
*/
  cout << "\n\n what is f3(5,f1)?  Answer: " << f3(5,f1);
  cout << "\n what is f3(5,f2)?  Answer: " << f3(5,f2);


  cout << "\n";
}