Given an Iterator class interface with methods:
hasNext(), design and implement a PeekingIterator that support the
peek() operation -- it essentially peek() at the element that will be returned by the next call to next().
Here is an example. Assume that the iterator is initialized to the beginning of the list:
[1, 2, 3].
next() gets you 1, the first element in the list.
Now you call
peek() and it returns 2, the next element. Calling
next() after that still return 2.
next() the final time and it returns 3, the last element. Calling
hasNext() after that should return false.
Follow up: How would you extend your design to be generic and work with all types, not just integer?
Special thanks to @porker2008 for adding this problem and creating all test cases.