$3-$ Build the index: It asks the user to enter a database name $($a random$-$access file$).$ It reads

the database records sequentially one at a time, and creates an ordered singly linked list in

the memory. Every node of the linked list will contain a pair $($KEY$,$ ADDRESS$)$ as well as a

reference to a node, where KEY is the student ID and the ADDRESS is the position of the

record containing that ID in the database $($the first record in the database is at position zero,

the second record is at position $1,$ and so on$).$

$4-$ Display the index: It asks the user to indicate whether he$/$she wishes to see the entire index or

part of the index. If the entire index is desired, it displays all the keys starting with the key in the

first node and ending with the key in the last node. If only part of the index is desired, it prompts

the user to enter the starting key. It searches the ordered singly linked list to find the node

containing that key. If the search is successful, it displays every key beginning with the starting

key and ending with the key in the last node. Otherwise, it displays a message indicating the

failure of the search