(finished ptr_play1.cpp)

(did a little function-with-a-pointer-parameter
example, get_double_at)

DYNAMIC memory allocation

*   the new operator, when followed by the name 
    a type, allocates a chunk of memory from
    the freestore or heap and produces/returns
    the address of that chunk of memory;

new double // allocates a chunk of memory able to hold
          //    a value of type double, and has as its
          // value the address of that chunk of memory
new int

new boa

Say that I have:

int *num_ptr;
num_ptr = new int;
*num_ptr = 84;  // now that chunk of freestore
                //    contains 84

BUT!!!!! What you have ALLOCATED with new,
YOU ARE EXPECTED TO FREE, or release, or clean up,
using:

delete

For example, here:

delete num_ptr;

YES, THIS IS A CLASS CODING STANDARS

ALSO:
once you have freed what a pointer is pointing to,
it is a good habit to then set that point to NULL:

delete num_ptr;
num_ptr = NULL;

*   see ptr_play2.cpp