Aug 1999 CA208 : 'C' Programming (Question 2)

You are to implement a student record database system for an Information Technology course. The system stores one record per student per course. There are four different subjects on the course : C programming (denoted by CA), Pascal Programming (denoted by AP), C++ programming (denoted by CPP) and Java programming (denoted by JPP).
(a)	Define a suitable enumerated type type, subject_type, which takes on the value of any of the four subject types denoted.	[1]
(b)	Declare a suitable data structure StudentRecord, for each student, which is capable of holding the following information: The students name, called student_name, which has a maximum length of 50 characters; The subject_type to which this record refers, called subject; The mark the student achieved in the examination for this subject, called mark. Pointers left and right, which will point to structures of this type to allow creation of a double linked list.	[5]
(c)	Given the definition of the double linked list which you are to use for storing your records : typedef struct { StudentRecord* leftmost; StudentRecord* rightmost; Double_linked_list; } Write a function void add_candidate(double_linked_list* mylist, StudentRecord* candidate); that takes in a StudentRecord, and adds it to the right of the list. You should assume the list being passed in is non-empty, and you should assume that since the candidate parameter being passed in is the same size as the list element being created, a memcpy will allow the structure to be copied once suitable space has been created.	[4]
(d)	Write a function StudentRecord* remove_candidate(int mark); that will take in the value of a mark, and remove and return the first occurrence in the list that it finds of a candidate scoring that mark. If no candidate is found scoring that mark, the function will return NULL.	[6]
(e)	Write a function sort_list, that takes a pointer to the list x, and a pointer to an empty list y, and, starting at the maximum mark of 60 and decreasing to the minimum mark of 0, will perform a sort. Each element matching the current mark should be removed from the original list, and added to the new list. The result will be that the list y will contain all of the records which were in x, but in decreasing order of marks.	[4]