K&B page 628 question 9

[Mamadou Touré]

Given a properly prepared String array containing 5 elements, which range of results could be proper invocation of Arrays.binarySearch() produce ?

A. 0 through 4
B. 0 through 5
C. -1 through 4
D. -1 through 5
E. -5 through 4
F. -5 through 5
G. -6 through 4
H. -6 through 5


I responded E (-5 through 4), but in the book the correct response is G(-6 through 4). Could someone explain me why G and not E ?

Regards

[Hemnathbabu Kottaiveedu]

Hi,

I guess you are clear with the most positive value that will be returned after a successful search i.e. 4 because there are only 5 elements present.

Now if we consider the results for negative values i.e. for the insertion of elements to maintain the sort order then there are three cases which we can have:

1. Insertion at the start of the Array i.e. at index 0 : In this case the binarySearch will return [-(insertion point)-1] i.e. [-(0)-1]=-1

2. Insertion at the end of the Array i.e. at index 5(Not 4 because a new element needs to be added) : For this the result will be [-(5)-1]=-6

3. Insertion at any place other than the above two: In that case the result will be between -2 and -5 both inclusive.

I hope you this should help you!!!

Thanks
Hemnath