Question

I was given a program which uses integer input to calculate Priority Queue.

How to rewrite code to represent object instead of integers?

The issue with my revision is that my modification fail to run and say

Answer 1

Your objects aren’t strings but integers (long). So don’t try to parse them.

You could change

  if( Long.parseLong((String) item) > Long.parseLong((String) queArray[j]) )

to

  if ((Long) item) > (Long) queArray[j]) )

You could also change

public void insert(Object item)

to

public void insert(Long item)

in order to avoid the cast.

But that wouldn’t work for other types of objects than Long so isn’t probably useful to you.

If you want to be able to compare any kind of object, you can provide a Comparator :

You would define PriorityQ as PriorityQ<T> (using generics), add a setComparator(Comparator comparator) method, and define your insert method like this :

 public void insert(T item)
 ...

 if ((comparator.compare(item, queArray[j])>0) {

This means changing also the queArray array to a T[] type.