binary search

[hari harann]

Given a properly prepared String array containing five elements, which range of results could a
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
Answer:
3 G is correct. If a match is found, binarySearch()will return the index of the element that was matched. If no match is found, binarySearch() will return a negative number that,
if inverted and then decremented, gives you the insertion point (array index) at which the value searched on should be inserted into the array to maintain a proper sort.
but i feel option G is incorrect, the answer is option E. am i right??

[Pranav Bhatt]

Hi Hari,
The range will be from -6 through 4 As the array is of 5 elements so if you insert any element that comes at last like ZZZ. This will give you -6 as it will come after the last 5th element. If you happen to insert the fifth element to get the highest range value you will end up with 4 as elements are from 0->4(5 elements). Check the below prog-:

import java.util.Arrays;
 
class test { 
public static void main(String[] args) {
String[] names = new String[]{"BOB", "JOE", "JIMMY", "FRED","TOAD"};
  System.out.println(Arrays.binarySearch(names, "TOAD"));
 System.out.println(Arrays.binarySearch(names, "ZZZ"));

}
}
    

[hari harann]

Thanks pranav

[Ankit Garg]

Hey Pravan I modified your code. I think this will make it more understandable.

import java.util.Arrays;
 
class BinarySearchTest
{ 
public static void main(String[] args)
{
String[] names = new String[]{"BOB", "JOE", "JIMMY", "FRED","TOAD"};
System.out.println(Arrays.binarySearch(names, "TOAD"));
System.out.println(~Arrays.binarySearch(names, "ZZZ"));
}
}

[Pranav Bhatt]

Hey Ankit, Its Pranav . Thanks for the modification, am bit lazy here