java.util.Comparator
java.util.PriorityQueue
java.util.Iterator
java.util.Iteratable
If you have not done so already, fork and clone the repo.
Write a new class with a main
method that creates a priority queue
of strings that is ordered by string length, adds a few strings,
and then remove sthe strings.
You may use either java.util.PriorityQueue
or BuiltinPriorityQueue
for your priority queue.
You should use an anonymous inner class to build the comparator for the
priority queue. If your compare
method is presented with two
equal-length strings, it should compare them alphabetically.
As you may recall, the ArrayBasedStack
class has two fields, an
array called values
and an integer called size
.
a. Sketch (that is, make notes on but do not write the Java code for)
an iterator for the ArrayBasedStack
class.
b. Compare your answer to the iterator presented in ArrayBasedStack.java
.
As you may recall, the LinkedQueue
class has two fields,
front
and back
, each of which reference a node.
a. Sketch (that is, make notes on but do not write the Java code for)
an iterator for the LinkedQueue
class.
b. Compare your answer to the iterator presented in LinkedQueue.java
.
You may have noted that the ArrayBasedQueue
class lacks an iterator.
Write one. Your iterator should present the elements starting and
the front of the queue and ending at the back.
Your code will likely look something like the following.
public ArrayBasedQueue<T> implements ... {
// ...
Iterator<T> iterator() {
return new ArrayBasedQueueIterator<T>(this);
} // iterator()
// ...
} // ArrayBasedQueue<T>
public ArrayBasedQueueIterator<T> implements Iterator<T> {
ArrayBasedQueue<T> abq;
int i;
public ArrayBasedQueueIterator(ArrayBasedQueue<T> abq) {
this.abq = abq;
this.i = 0;
}
// ... this.abq.values[this.pos] ...
}
remove
in array-based queuesYou may have noted that java.util.Iterator
provides a remove
method.
Implement that method for your iterator for ArrayBasedQueue
.
Convert your iterator for array-based queues to an anonymous inner class. You should now be able to do without the field that refers back to the associated array-based queue.
It seems unlikely that you will have extra time. If you do, you may leave early.
This lab was newly written in spring 2019. (Can you tell?)