CS1500 Algorithms and Data Structures for Engineering, FALL 2012
 LAB 7: Double Linked Lists  As a special case of particularly
important topic, LAB7 must be completed by all students, even if
late (the sooner the better).  30 points total, might fail the
course if not completed.  FIRST PART OF LAB7 (one lab)  You have
to build a car inventory using a double-linked list. A) First
design a struct/class called carobject that can be linked both
ways (has next and prev pointers), and that contains the data
members B) Write a function that appends a new car to the
inventory. Your inventory list *must be sorted by year* at all
times, so the new car will be inserted in the list at
appropriate location, rather than simply appended at the end.
void car_append (int ID, char* brand, int year, int price,
carobject** listhead)  C) Write a function that lists all cars
in the inventory with a certain manufacturing year. You should
take advantage of the fact that the list is sorted by year void
listallcars_by_year (int year