1. Write set() for a CircularArrayList:

     ,----
     | public class CircularArrayList<T> implements List<T>{
     |   int theArray[];
     |   int numElem; //number of elements
     |   int head; //index of head of list
     | 
     |   //...
     | 
     |   T set(int i, T v){
     | 
     | 
     |   }
     | 
     | }
     `----