Question

Write java class “BinarySearch” that uses recursion to find the index of a target value in

an ascending sorted array. If not found, the result is -1. The array has to be unsorted before you sort it.

Use “ BinarySearchDriver.java” to drive the “BinarySearch” class

/*************************************************************

* BinarySearchDriver.java

* Student Name

*

*.

*************************************************************/

public class BinarySearchDriver

{

public static void main(String[] args)

{

    int[] array = new int[] {55, 88, 33, 5, 8, 12, 16, 23, 45}; /unsorted array

    System.out.println(BinarySearch.binarySearch(

      array, 0, (array.length - 1), 16));

    System.out.println(BinarySearch.binarySearch(

     array, 0, (array.length - 1), 50));

}

}

Answer 1

public class BinarySearch {
  public static int binarySearch(int[] input, int low, int high, int key) {
    int mid;
    if(low<=high){
      mid = low + (high-low)/2;
      if(input[mid] == key){
        return mid;
      }
      else if(input[mid] < key){
        return binarySearch(input,mid+1,high,key);
      }
      else{
        return binarySearch(input,low,mid-1,key);
      }
    }
    return low+1;
  }

}