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BinarySearch()

ahmed yehia
Ranch Hand

Joined: Apr 22, 2006
Posts: 424
Question no. 9 chapter 7 k&B

Given a properly prepared String array containing five elements, which range of results could a proper invocation of Arrays.binarySearch()produce?
answer: -6 through 4

per my understanding answer should be (-5 through 4) since inserion points evaluates as (-(insertion point) -1), so for eg last insertion point of index 4 should be (-4 -1) which is -5 Not -6
Sanjeev Singh
Ranch Hand

Joined: Nov 01, 2006
Posts: 381
Not all person may have the book with them while reading posts.
Please make a practice to post the questions also.


~Sanjeev Singh<br />SCJP 1.5
ahmed yehia
Ranch Hand

Joined: Apr 22, 2006
Posts: 424
Originally posted by Sanjeev Singh:
Not all person may have the book with them while reading posts.
Please make a practice to post the questions also.


There is no actual question, only the statement that I mentioned.
Burkhard Hassel
Ranch Hand

Joined: Aug 25, 2006
Posts: 1274
Howdy ranchers,

Ahmed wrote
per my understanding answer should be (-5 through 4) since inserion points evaluates as (-(insertion point) -1), so for eg last insertion point of index 4 should be (-4 -1) which is -5

No, the last insertion point is behind the last entry, so if you have a sorted collection say:
(0, 1, 2, 3, 4)

and you do a binary search for number 5, which isn't in. Then the insertion point would be index 5 (after the four)
And as the returned value of a not-find is always
-(insertion point - 1)
the binary search should return -6.



Yours,
Bu.
[ July 19, 2007: Message edited by: Burkhard Hassel ]

all events occur in real time
saravana.T kumar
Greenhorn

Joined: Jul 13, 2007
Posts: 23
HI,

binarySearch(List<? extends Comparable<? super T>>

checkedMap(Map<K,V> m, Class<K> keyType,)

checkedSortedSet(SortedSet<E> s, Class<E> type)

these methods were taken from the collections class

MY doubt is the arguments
1.List<? extends Comparable<? super T>
2.checkedMap(Map<K,V> m, Class<K> keyType,)
3.(SortedSet<E> s, Class<E> type)

In this forum i read that <E> is for numeric types is it true?


and please explain what these arugments types expect.
Burkhard Hassel
Ranch Hand

Joined: Aug 25, 2006
Posts: 1274
Howdy ranchers!

Saravana asked:
In this forum i read that <E> is for numeric types is it true?

No. You must have misunderstood something. It is a generic type. On the Sun site is a tutorial part also about Generics. You'll need to spend some time with this for the exam.

Yours,
Bu.
 
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subject: BinarySearch()