Implement Binary Search in Java using recursion.

// Java Program to Illustrate Recursive Binary Search
// Importing required classes
import java.util.*;
// Main class
class GFG {
// Method 1
// Recursive binary search
// Returns index of x if it is present
// in arr[l..r], else return -1
int binarySearch(int arr[], int l, int r, int x)
{
// Restrict the boundary of right index
// and the left index to prevent
// overflow of indices
if (r >= l && l x)
return binarySearch(arr, l, mid – 1, x);

// Else the element can only be present
// in right subarray
return binarySearch(arr, mid + 1, r, x);
}
// We reach here when element is not present in
// array
return -1;
}
// Method 2
// Main driver method
public static void main(String args[])
{
// Creating object of above class
GFG ob = new GFG();
// Custom input array
int arr[] = { 2, 3, 4, 10, 40 };

// Length of array
int n = arr.length;
// Custom element to be checked
// whether present or not
int x = 10;
// Calling above method
int result = ob.binarySearch(arr, 0, n – 1, x);
// Element present
if (result == -1)
// Print statement
System.out.println(“Element not present”);

// Element not present
else
// Print statement
System.out.println(“Element found at index ”
+ result);
}
}