Computer Science 215
                               Quiz E      Name ______________________


1. Suppose the location of the viewpoint is V and the world coordinates
   of point on the screen through which a ray passes is W.
   A unit vector in the direction of the ray is then given by

   a.  V / ||W||                      b. W / ||W||

   c. (W - V) / || W - V ||           d. (V - W) / || V - W ||

2. The location of the hitpoint H is given by H = B + tD where

   a. B represents the point where      b. D represents the point where
      the ray passes through the           the ray passes through the
      screen and D is a unit vector        screen and B is a unit vector
      in the direction of the ray          in the direction of the ray

   c. B represents the viewpoint        d. D represents the viewpoint
      and D is a unit vector               and B is a unit vector
      in the direction of the ray          in the direction of the ray

3. If a C program mallocs an area of memory and fails to free it,

   a. A garbage collector built         b. The OS will reclaim all of the
      into the C language will             memory used by the program including
      reclaim it                           unfreed malloc'd areas when
                                           the program exits.

   c. The memory will remain unusable   d. The memory will remain permanently
      until the system is rebooted         allocated and the computer will
                                           eventually have to be sent back to
                                           the factory for memory replacement

4. The correct approach to avoiding memory leaks is to free a malloc'd object

   a. whenever a function that has      b. whenever the LAST pointer to the
      a local variable that points         object is about to be reset or to
      to it returns                        go out of active scope.

   c. both of the above are true.

5. Assuming "lst" points to the head of one of our object lists, which
   best characterizes the following code fragment:

   obj_t *temp = malloc(sizeof(obj_t));
   temp = lst->head;

   a. it will cause a memory leak        b. it will cause a seg fault

   c. it is the correct way to
      set temp to point to the
      first object in the list.