#include <stdio.h>

int main ()
{
    int foo = 42;
    int bar = -1;
    int * foo_ptr;

    foo_ptr = & foo;

    printf ("Get the existing values of foo, bar, foo_ptr, and * foo_ptr:\n");

    printf ("foo = %d\n", foo);
    printf ("bar = %d\n", bar);
    printf ("foo_ptr = %p\n", foo_ptr);
    printf ("* foo_ptr = %d\n", * foo_ptr);

    printf ("Change the value of * foo_ptr:\n");

    * foo_ptr = 99;

    printf ("foo = %d\n", foo);
    printf ("bar = %d\n", bar);
    printf ("foo_ptr = %p\n", foo_ptr);
    printf ("* foo_ptr = %d\n", * foo_ptr);

    printf ("Change the value of foo_ptr to & bar:\n");

    foo_ptr = & bar;

    printf ("foo = %d\n", foo);
    printf ("bar = %d\n", bar);
    printf ("foo_ptr = %p\n", foo_ptr);
    printf ("* foo_ptr = %d\n", * foo_ptr);

    return 0;
}