hacktoberfest-2018/code/aka4rKO.java

// Java implementation of recursive Binary Search 
class BinarySearch 
{ 
    // 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) 
    { 
        if (r>=l) 
        { 
            int mid = l + (r - l)/2; 
  
            // If the element is present at the  
            // middle itself 
            if (arr[mid] == x) 
               return mid; 
  
            // If element is smaller than mid, then  
            // it can only be present in left subarray 
            if (arr[mid] > 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; 
    } 
  
    // Driver method to test above 
    public static void main(String args[]) 
    { 
        BinarySearch ob = new BinarySearch(); 
        int arr[] = {2,3,4,10,40}; 
        int n = arr.length; 
        int x = 10; 
        int result = ob.binarySearch(arr,0,n-1,x); 
        if (result == -1) 
            System.out.println("Element not present"); 
        else
            System.out.println("Element found at index " +  
                                                 result); 
    } 
} 
/* This code is contributed by Rajat Mishra */