$1.$ The LinkedList.java file presents the interface for the SList.java class.

$($a$)$ Provide an implementation for a $$findIndex$$ method in the SList.java class

public int findIndex $($int elem$)$

that returns the position of a specific element if it is a member in the list, otherwise it will return $(-1).(3$ points$)$

$($b$)$ Provide an implementation for the $$removeLast$$ method in the SList.java class